Journeys into the Ring of Fire_3of4_Peru
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00:00As a geologist, I'm fascinated by rocks, but it's not just where they've come from and
00:17what they're made of, it's the fundamental role they've played in shaping human history.
00:24In this series, I'm travelling around the Pacific Rim on a quest through some of the
00:29most dramatic and exotic locations on Earth to discover how civilisation has been moulded
00:35by the rocks beneath us.
00:43It's brought me to the rugged, vertical landscape of the Peruvian Andes, holding to the highest
00:50peaks of the Western Hemisphere in some of the world's most unpredictable and destructive
00:55climates.
01:01It's a land shaken by earthquakes and devastated by volcanoes, yet 500 years ago, this inhospitable
01:08terrain was mastered by the Incas.
01:13The Inca civilisation built a magnificent empire, equivalent to ancient Rome's, in
01:18one of the most hostile places on the planet.
01:23I'm going to journey through modern Peru, from coastal desert to oxygen-starved peaks.
01:28I want to uncover the geological challenges that they faced and discover the secret of
01:34the Inca's triumph.
01:44On the eastern edge of the Pacific Rim, the South American continent is shaped by the
01:487,000-kilometre-long Andes mountain range.
01:54These mountains were the spine of the Inca Empire.
01:59To grasp the implications of this, I've come to look at a hole in the ground.
02:09If that stone keeps falling down to the deepest part of this great gash in the landscape,
02:14it will have dropped more than 4,100 metres.
02:17It's almost 13,500 feet.
02:20This is the Colca Canyon.
02:27The deepest canyons in the world lie crumpled in the heart of the Peruvian Andes.
02:36It's so difficult to get a sense of scale in this vast space, but to give you an idea,
02:41over there, that white patch clinging to the other side of the canyon, is a village.
02:53The Colca Canyon is twice as deep as the Grand Canyon in America.
02:58It's home to these magnificent condors, the largest birds of prey in the world.
03:18Coping with the heights and chasms of the Andes was just one part of the geological
03:23challenge that confronted the Incas.
03:30Along the line of the Andes, there's a chain of dozens of active volcanoes, all capable
03:35of erupting.
03:36There's one volcano up there, Mount Hualcahualca, and over here, down in the canyon, you can
03:42see the vertical columns of a massive lava flow.
03:47What's more, the ground beneath me is frequently shattered by terrible earthquakes.
03:53I find it extraordinary that the Incas not only survived in this volatile geological
03:58setting, they thrived in it.
04:05More than 10 million people lived under Inca rule, and villages and towns nestled amongst
04:10the Andean peaks.
04:18I want to know how they constructed buildings that survived the violent seismic activity
04:22of this region.
04:27How did they grow crops to feed their millions on such steep slopes, in such a hostile climate,
04:33and at such high altitude?
04:38How did they manage to link up the far-flung corners of their vast empire, an empire that
04:43sprawled over nearly a million square kilometers of geological extremes?
04:52By 1530, the Inca Empire covered not just most of what is now modern Peru, but much
04:59of what became Bolivia, Chile, and even parts of Argentina and Ecuador, a realm ruled by
05:06emperors who claimed divine descent from the Inca sun god.
05:15Within its borders lay an extraordinary mix of ecological and geological zones, from snow-capped
05:22mountains to arid deserts.
05:27The remains of the great Inca Empire can be found even here, rising from the sands of
05:32Peru's Pacific coast.
05:36What marked the Incas out from all the Andean civilizations that had preceded them was how
05:41they mastered highland and lowland.
05:44I'm hoping that by looking at some of these ecological zones, I'm going to get a better
05:48understanding of how they did it.
05:50And I'm going to start down there, with a journey along Peru's great coast, on the Pan-American
05:56Highway.
06:07My first task is to find out how the Incas were able to keep their empire fed when challenged
06:12with such unforgiving terrain.
06:19Lucho is our driver on this journey, and the landscape he reveals as we drive alongside
06:24the Pacific is unique.
06:27Almost all coastal Peru is the same, bleak desert, little rain, and just as it was 500
06:33years ago, mostly impossible to farm.
06:36But for the Incas, this barren coast was still a vital resource, and it was all down to geology.
06:45Parallel to this road, there lies a deep oceanic trench that channels unusually cold water
06:51along these shores.
06:52This cold water sustains conditions perfect for an abundance of fish.
06:57In fact, these are the richest fisheries in the world.
07:06Five hundred years ago, the vessels that fished Peru's waters couldn't be made out of wood.
07:12Trees are rare on this desert coast, it's just too dry.
07:16But the Incas had a way around this shortage.
07:20Their fishermen made boats out of reed.
07:25The original design, unchanged since Inca times, is still used in a few places today.
07:31These are the Caballitos de Tortora, horses of reed.
07:35Hello!
07:36Hola!
07:37Hi, I'm Ian.
07:38Nombre Ian.
07:39Nombre Luis.
07:40Luis, hiya.
07:41Caballito.
07:42This is it, caballito.
07:43Grande.
07:44It's very grande, isn't it?
07:45Grande.
07:46Gosh, amazing.
07:47Quieres?
07:48Yeah, yeah, let's go.
07:49Yeah, could we?
07:50Si, si.
07:51Go ahead.
07:52El agua.
07:53Yeah, I'm looking forward to it.
07:54It must be very strong.
07:55Is it cold?
07:56It's cold.
07:57The trick of it, as Luis attempts to explain, is to always point the nose of the caballitos
08:21towards the oncoming waves.
08:27Get caught side on and you find out how cold the waters offshore really are.
08:38Luis and the fishermen here need only a couple of trips a day into these bountiful waters
08:43to sustain their communities.
08:47In theory, there's enough fish off this coast to feed an empire as large as the Incas.
08:54Perhaps they didn't need to bother with those inhospitable mountains after all.
08:57The coastal people here have the knowledge and skills to fish these waters and make the
09:04most of what these arid shores have to offer, but there's one problem, El Niño.
09:13For centuries now, Peruvian fishermen have noticed that every few years the waters offshore
09:18get warmer.
09:21Usually this happens around Christmas time, so they started calling this warming El Niño,
09:25the infant, after the Christ child.
09:30We now know that the knock-on effects of El Niño are global, from flooding in California
09:37to drought in Indonesia, but Peru's Pacific coast is where the phenomenon originates.
09:44It starts with a weakening of the normal coastal trade winds.
09:48I'm not really sure why it happens, but we know the result.
09:52The waters out there get warmer by about 10 degrees centigrade, distorting weather around
09:58the world.
09:59The impact here in Peru is devastating.
10:10The warm El Niño waters change the balance of life in the seas.
10:15Plankton die out and fish levels plummet.
10:19The Incas would have faced this problem too, making reliance on fishing alone far too risky.
10:29For a sense of the El Niño effect in Inca times, I've come to the modern Peruvian fishing
10:34port of Chimbote.
10:35In 1972, 20% of global fishing took place in these waters.
10:43Then came the worst El Niño in recorded history.
10:51It wiped out nearly 90% of Peruvian fish stocks, and just as it was getting back on its feet,
10:58the fishing industry here was hit by another severe El Niño.
11:05Many of the boats in Chimbote now spend several months of the year becalmed and inactive.
11:11There's no way to predict when this El Niño effect is going to happen.
11:17It can arrive at intervals of anything between 2 and 11 years, and it can last up to 18 months.
11:26But for the Incas, depending on coastal fishing alone would have been a flawed strategy.
11:31To feed their empire, they had to find ways of exploiting their natural home in the inhospitable
11:36mountains, and that would be no easy task.
11:41I'm heading eastwards and up into the Andes, to Peru's fabled white city, to discover how
11:47the Incas did it.
11:57As we drive inland and uphill, I'm becoming aware of just how difficult this place must
12:03have been for the Incas to farm.
12:10There are steep slopes, poor soils, and the weather here is just as unhelpful as it is
12:16down on the coast.
12:18In Peru, each altitude zone has been given its own name.
12:22As we ascend between 500 metres and 2,300 metres, we drive through the Yunga zone.
12:28But we're heading higher still, into the Quechua zone.
12:38This is our destination, Arequipa.
12:48The White City.
12:51Buildings here are made from a white volcanic rock called sila.
12:59Above this thriving modern city, the perfect cone of the volcano Mount Misty.
13:05As legend has it, ancient Arequipa was named by an Inca emperor on his way back from a
13:21war of conquest.
13:23Exhausted, he arrived here and said, in the Inca language, Arequipe, which means, OK,
13:29let's stop here.
13:31Now that's a good idea.
13:34Arequipa is at 2,300 metres, the start of the Quechua zone, which extends upwards to
13:403,500 metres.
13:44That's about three times the height of Mount Snowdon in Wales, which to those that live
13:48around here, is a small hill.
13:51In Inca times, most people lived in this Quechua zone.
13:56Successfully cultivating the land at this altitude was a matter of life and death for
14:01the Incas.
14:03To find out how they did it, I'm meeting up with Juan Osio, one of Peru's most eminent
14:08historians.
14:11Although I'm a little anxious about the Inca delicacy he's lined up for lunch.
14:16So tell me more about this.
14:18Well, you know, the name of this is cuy.
14:21And it has been known now in the wider world as a guinea pig.
14:26And this was a delicacy for the Incas.
14:29It was an extremely tasteful horse.
14:32I normally have my guinea pigs on a wheel.
14:34I've never had them around.
14:37So what were the challenges about growing food in this Quechua zone?
14:41Well, the main problem, I think, is the unpredictability of the weather.
14:47Either severe drought that may produce frost, or if you have an excessive amount of rain,
14:54the problem is that the crops that were grown by the Andean people may get rotted.
14:59So either too little rain, drought, or too much rain.
15:02That's the problem.
15:03It seems a very fragile environment.
15:05How did they manage to manage that?
15:07The solution to sort out this problem was to develop land terraces.
15:12Land terraces?
15:13Land terraces.
15:14Fantastic.
15:15In the countryside around Arequipa, we can see how that Inca solution has transformed the landscape.
15:30Everywhere there are terraces.
15:35And terraces.
15:38And terraces.
15:40And terraces.
15:43Terraces.
15:50It's said that the Incas approached farming with weapons in their hands and prayers on their lips.
15:57To them, agriculture was like warfare.
16:00A victory claimed by disemboweling the earth.
16:14So Juan, these terraces are absolutely stunning.
16:17Well, they are indeed beautiful.
16:19But how do they work? What's the job?
16:21Well, you know, they accomplish different purposes.
16:23One of the purposes was to face the unpredictability of the weather.
16:28Another one was to expand the agricultural production, because as you can see, the slopes are very steep.
16:35So this is a good alternative for making those slopes productive.
16:40Beyond that, there is the problem of erosion as well.
16:43So what, they stabilize the slope?
16:44It stabilizes extremely well.
16:47So in terms of the unpredictability of the weather, what do they do? Do they capture the rainfall?
16:52Not the rainfall, but the water coming from the mountains.
16:56So the mountain streams is what feeds these?
16:58The mountain streams, exactly.
17:00Irrigation like this, using water diverted from streams, is much more reliable than rainfall.
17:07As in Inca times, maize, that's corn, is the staple crop grown on these terraces.
17:15Juan has asked Don Geraldo, a local farmer,
17:18if we can attend an Inca ritual still performed when maize seeds are selected for planting.
17:28This is a private ritual, a practice that's widespread here but rarely seen by outsiders.
17:37Good morning.
17:39Good morning.
17:43There is no crop so important as maize.
17:46This seed is so important that it has been treated very specially.
17:52And this is chicha?
17:54And that is chicha.
17:56Chicha, a beer brewed from maize, is at the sacred heart of the ceremony.
18:01He's offering to each of the mountains.
18:05And then to the maize.
18:11And now he spills sand to the ground because that's the Mother Earth that is receiving as well.
18:16Pachamama, that's the pachamama.
18:19And then he drinks, obviously.
18:21He has to drink the whole thing.
18:23The whole thing?
18:24The whole thing, yes.
18:29Wow.
18:32It's your turn.
18:34Thank you very much.
18:38Is it strong?
18:39No, it's very soft. This one is mild.
18:46It's quite strong, actually.
18:49Chicha yanqueña.
18:59Muchas gracias. Muchas gracias.
19:03I read, I don't know if this is true,
19:05but in Inca times the emperor had these virgins of the sun that chewed the maize and fermented the chicha?
19:11That is true because saliva helps to ferment the chicha
19:16and it's something that has continued even to our times.
19:20So do you think this chicha was chewed by these ladies?
19:23I doubt. I imagine that this chicha has been prepared in a different way.
19:29Good. That makes me feel a little better.
19:36Well, now they continue with the selections of the seeds
19:40and that is a job performed exclusively by women.
19:44Men are never allowed to touch seeds.
19:47To touch the seed?
19:48They are not allowed.
19:59Farming these slopes is a constant struggle.
20:02To thrive, maize needs a warm and humid climate and a relatively long growing season.
20:08Neither are assured at this altitude.
20:12Every year the crops are menaced by drought while frost remains a constant threat.
20:20As with the fishing at the coast,
20:22the Incas couldn't guarantee that the terraces would provide for their vast population in any given year.
20:28They needed to exploit every possible food source wherever they found it.
20:34So Lucho and I are off again, heading uphill.
20:42As we drive higher, the mountains have become even more hostile.
20:50At this level, maize can't grow and the soil is difficult to terrace.
20:55Yet Inca farmers still saw great potential in these highlands.
21:02We've now entered what's called the sunny zone,
21:05We've now entered what's called the sunny zone,
21:07which lies between 3,500 and 4,000 metres.
21:12That's about three times the height of Britain's tallest mountain, Ben Nevis.
21:20The temperature here regularly dips below zero.
21:23Shadows from passing clouds can reduce it by 15 degrees centigrade in a moment.
21:30But the Incas had a very special crop
21:33that meant this sunny zone gave them some of their most productive land.
21:37To find it, I'm off shopping.
21:46What strikes me about markets here is the amazing range of produce.
21:54In fact, it's thought that Andean inhabitants were the first to cultivate
21:58as many as half of the agricultural products the world grows today.
22:03They are inventing this a direct response to the challenging landscape around them.
22:10And in the sunny zone, one crop thrives.
22:15The humble spud.
22:19The potato was first cultivated in the Andes,
22:21and there are hundreds of different varieties in these mountains.
22:25Because it grows underground, a tuber, like the potato,
22:28is protected from the bitter nighttime cold at this altitude.
22:33Hello.
22:34Hello.
22:35What is this?
22:36Oyoko.
22:37Oyoko.
22:38Oyoko.
22:39Oyoko.
22:40Oyoko.
22:41Okay.
22:42Three?
22:43Let's see.
22:44Three?
22:45They look nice.
22:46This?
22:47Oca.
22:48Oca?
22:49Oca.
22:50Okay, oca.
22:51That looks fantastic.
22:52Look at that.
22:53What is it?
22:54Maca.
22:55Maca.
22:56Maca.
22:57This is Maca.
22:58I hear this is an aphrodisiac.
23:00Bueno?
23:01Bueno.
23:02Bueno?
23:03Mucho bueno, eh?
23:04Dos.
23:05I better have...
23:06Try two.
23:07Cinco.
23:08Cinco solas?
23:10Muchas gracias.
23:11Adios.
23:14By capitalising on the sheer diversity of produce,
23:17from maize and other crops in the low valleys
23:20to potatoes and related tubers up here,
23:22the Incas mastered survival at heights up to 4,000 metres.
23:27But they didn't just stop there.
23:29Some of the most important land was to be found higher still.
23:32And to get there, we're going to have to abandon the car
23:35and use the more traditional means of getting round the Andes.
23:53I've persuaded Lucio, our driver, to continue as my guide.
23:58These animals must walk slowly.
24:00Right.
24:05It's a bit of a traffic jam here.
24:08Oops.
24:14Ah, you use this, do you?
24:16Oh, sh...
24:20The Incas never used wheels for transport.
24:23As I hike up the rocks and ruts of this mountain trail
24:26I'm beginning to understand why.
24:32We're going to climb higher into the Puna zone,
24:364,000 metres and above.
24:39Few staple crops can grow in the Puna,
24:41but the zone was vital to the Incas.
24:44The reason?
24:45These pack animals, llamas.
24:49Or as we say in English, llamas.
24:52These animals were at the heart of the Inca economy.
24:56The Puna zone is where the llamas like to graze.
24:59They love the tough Ichu grass which grows at this altitude.
25:05Llamas were a vital supply of leather and wool.
25:09They were even used as an offering to the Inca sun god.
25:12Every month, hundreds were sacrificed to appease him.
25:17They were crucial for carrying cargo.
25:21The Inca army used supply trains of thousands of llamas.
25:26And when they were no longer needed for porterage, they were eaten.
25:31I had an idea for a menu tonight, and one of these llamas
25:34has got some tubers that I bought at the market.
25:37It's in... I don't know, one of the white ones, I think.
25:40OK.
25:42Fortunately for our woolly friends,
25:44tonight's meal will be strictly vegetarian.
25:49So what's in the pot, then?
25:50Yeah, we have some tubers.
25:52This is oca.
25:53Oca. OK.
25:57Oh, it's nice. It's quite sweet.
25:58Yeah.
25:59It's quite sweet.
26:00If you put some sugar, it's better.
26:01Sugar? With potato and sugar?
26:03Yeah, yeah.
26:04Here we have some maca.
26:05Ah!
26:07I've heard about this.
26:09Yeah?
26:10I'm not sure I should.
26:12I'm not sure I should.
26:14You know, there's, what, five men and eight llamas,
26:16and I'm taking maca?
26:17Is it really an aphrodisiac?
26:19People say that it is.
26:21Should I try this?
26:22Maca?
26:24No, he's saying no.
26:25Lucio, maca?
26:26They're all saying no.
26:27I don't think I should try this.
26:29The tubers and potatoes on the menu tonight
26:31are high in carbohydrate, an excellent source of energy.
26:35And I'm going to need it.
26:37Tomorrow, we're going to attempt a difficult climb
26:40to the roof of the Inca world,
26:42a place higher than I've ever been in my life.
26:48It's really hot out there today,
26:50but it's going to get very cold tonight.
26:52Temperatures outside of the tent
26:53are going to go down to minus five degrees centigrade.
26:56So I'm all wrapped up, and I'll see you in the morning.
27:11MUSIC SWELLS
27:13MUSIC FADES
27:39We've climbed to about 4,300 metres,
27:42which is about 14,500 feet.
27:47If I seem a little breathless,
27:49it's because at this high altitude,
27:52the air is beginning to get much thinner.
27:55MUSIC SWELLS
28:12Every breath I take feeds less oxygen to my brain,
28:16and I'm in danger of suffering from altitude sickness, or hypoxia.
28:21The symptoms are headaches, shortage of breath,
28:24nausea and dizziness.
28:27I mean, I feel all right, but I've certainly lost my appetite,
28:30and I don't think it's anything to do with last night's meal.
28:34But I do feel weak.
28:36And the thing is, left to its worst, hypoxia can put me in a coma.
28:42MUSIC SWELLS
28:48But there was something remarkable about the Incas,
28:51and it's been passed on to their modern descendants.
28:54Compared to a lowlander like me,
28:56Andean people have hearts and lungs which are proportionately larger
29:00and take in more oxygen, adaptations shaped by their mountain home.
29:05For our guides, evolution has been influenced by geology.
29:10So, Lucho, how are you feeling?
29:13Good. I'm OK.
29:15These guys, they're just bounding up. Yeah.
29:27There may have been another secret to Inca resilience,
29:30and it's nothing to do with biological adaptation.
29:34Lucho?
29:36I think it's time for those coca leaves. Really?
29:39I've got a terrible headache.
29:41I'm going to bring you some.
29:43This is not cocoa as in chocolate, but coca as in cocaine.
29:48Can you make cocaine from this? I mean, I think in Britain this is illegal.
29:51No, it's legal here.
29:53For cocaine, you must mix with chemicals.
29:55So it's a long process. This is natural.
29:57So it's legal here in Peru.
29:59You put it in your mouth. Uh-huh.
30:01And after, you start to roll it.
30:04Roll it.
30:06It's not going to blow me away? No, like a coffee.
30:09Like a coffee? Yeah. OK.
30:11I'll have a coffee. Want to get more?
30:13More? OK.
30:15Coca leaves are a stimulant.
30:17A rolled wad of chewed leaves will provide my body with an energy boost.
30:21And the very act of chewing for several hours
30:24can accelerate the digestion of high-carb foods like last night's potatoes.
30:37I've been chewing these coca leaves for about three hours now.
30:40My mouth is completely numb.
30:43But my headache's gone, and I'm feeling kind of energetic,
30:47which is surprising, because this is the highest that I've been in my life.
30:57We've just passed the top of the Puno Zone,
31:00the highest point in the world.
31:03We've just passed the top of the Puno Zone at 4,800 metres.
31:15We're now higher than any peak in Europe.
31:22Because it's warmer here, near the equator, we're still below the snow line.
31:34Above this point is the Yanka Zone.
31:37Even the Incas had no need to venture up there.
31:40No crops would grow, and there was no possible grazing for the llamas.
31:49This is as high as I go.
31:51On my journey from this coast up into the mountains,
31:55I've learned that these altitude zones are incredibly challenging to farming.
31:59The climate, totally unpredictable.
32:02The Inca solution was to spread the risk.
32:08They realised that if they exploited a number of different altitudes at the same time,
32:12it would not matter if one failed.
32:15The others might remain unaffected and keep the empire fed and stable.
32:19The trick was to think vertically.
32:23The Incas didn't just understand this, they actively studied it.
32:27And we know this because of the existence
32:29of one of the most remarkable archaeological sites in Peru.
32:32And thankfully, it's not up here, it's down there, where there's more oxygen.
32:49This is Moray.
32:51Moray.
32:58At first glance, these terraces, a succession of perfect concentric circles,
33:03seem like the remains of a religious site.
33:10But this was something far more surprising.
33:14500 years ago, this was a lab.
33:17A greenhouse.
33:19A relic of the Incas' agricultural prowess.
33:25Here, the Incas discovered that they could recreate
33:28the different range of soils, temperatures and other variables
33:31found throughout the Andes.
33:33This was an experimental station where they could see which crops could survive where.
33:38And it was also a place where they could develop new strains
33:41to suit specific altitudes and conditions.
33:50In just this one small area, there could be as many as 20 ecological zones.
33:56All made possible by the particular geology of the site.
34:01The permeable limestone underneath soaks up the surface water
34:05and because it's slightly acidic, it dissolves away the rock,
34:08leaving behind these holes or craters in the landscape.
34:13The concentric nature of these bowls means that they capture sunlight and shade
34:18in a way that duplicates huge temperature variations.
34:22Just 30 metres separates the top and bottom terraces
34:26and yet a 15 degree centigrade difference in temperature has been recorded.
34:32Down there, growing conditions replicate the Quechua zone
34:36at around 2,600 metres,
34:39where I'm standing, it's more like the frosty Puna zone at 4,000 metres.
34:49The Incas probably measured the temperature differences
34:52by placing water in containers to freeze on the terraces overnight
34:56and monitoring the rate of thaw in the morning sunshine.
35:03What amazes me as a geologist is how the Incas managed
35:06What amazes me as a geologist is how the Incas
35:09turned this rugged topography to their advantage.
35:12The challenging Indian landscape was the problem
35:15but it also provided its own solution.
35:18The essence of survival here was variety.
35:23Through cleverly experimenting with crops and exploiting different altitudes,
35:27the Incas found ways to grow food for their millions.
35:31In fact, they could even produce a surplus.
35:36This was an amazing achievement
35:38but it only solved part of their geological challenge.
35:42They needed to develop a storage and distribution network for their food
35:46but how could they manage to do it in a place as rugged as this?
35:56I've come to the village of Ollantaytambo to find out.
36:01It's a good place to look for clues because it's a bit like a walk back in time
36:05and taking it with me is Peter Frost,
36:07an English historian who's made Peru his home for 18 years.
36:13So what's so special about this Ollantaytambo then?
36:16Well, it's unique really because it's the only Inca settlement
36:20with an Inca town plan, the Inca streets, the Inca courtyards in many cases
36:25which is still inhabited by people.
36:29Each one of these blocks would have been an Inca cancha, as they call them,
36:34like a courtyard with a number of buildings facing inwards.
36:39Each of these inhabited by different members of the same kinship group.
36:49Ollantaytambo allows us a real insight into how the Incas organised their villages.
36:55And because the site is so well preserved, it reveals exactly how they stored their surplus food.
37:02The system that was developed by the Incas made it safer.
37:06They weren't so subject to famine and disaster,
37:08which is one of the ruling factors in the Andes.
37:11They stored their agricultural surplus in a vast network of storehouses
37:16that were scattered throughout the empire.
37:18There's one right there on that mountain, you see?
37:20It's just above the mountain.
37:22It's right there on that mountain, you see?
37:24It's just above the trees over there.
37:27There's three rows of storehouses there.
37:31So precariously balanced on the rock face, that's where they put their warehouses.
37:35Yes, they built them in high inaccessible places for a variety of reasons.
37:40Firstly, it was a good place to keep produce fresh because it was windy and cool.
37:46It was also inaccessible so that unauthorised people couldn't get to it very easily.
37:51And another is perhaps to make it very prominent
37:54so that people are very always aware that these storehouses are there for their benefit.
37:59So like a big neon sign saying, Inca will look after you or something?
38:03In a sense, yes.
38:06So Inca storehouses acted like shock absorbers to stabilise their empire,
38:12providing access to food in times of poor harvests, adverse weather and famine.
38:18But without a means of distribution, these storehouses were of little use.
38:23And for that, the Incas needed roads.
38:28It seems inconceivable in the difficult terrain of the Andes,
38:32but the Inca empire was bound together by a 40,000 kilometre road network.
38:37And as the Incas hadn't developed a wheel, these roads were designed for travel by foot.
38:43They were engineered with sophisticated drainage
38:46and kilometres of steps were built for the slopes, all done with simple bronze tools.
38:53These roads could be used to transport food and were a key means of administering the empire.
38:58State officials travelled along them and so did information.
39:03Special couriers called chaskis would transmit messages across the empire
39:08by running relays along roads like these.
39:11They operated from stations at regular intervals
39:14and could cover 240 kilometres, that's 150 miles each day,
39:19which is hugely impressive given this rugged landscape.
39:25Chaskis were trained from childhood to remember verbal messages perfectly.
39:29Flawless accuracy was always guaranteed
39:31because they would suffer severe punishments if errors crept in.
39:37Verbal messages were not the only thing the chaskis relayed.
39:40They also carried these pieces of knotted string called quipus.
39:44These were enormously important to the Incas because they didn't have a written language.
39:49So they used the knots in these quipus to record statistical information
39:54vital to the running of the empire.
39:56For example, how much was contained in each of the storehouses in times of emergency.
40:04It seems as if the Incas had developed a system
40:07that mastered the difficulties of building an empire at high altitude.
40:13But unfortunately for them,
40:15extreme weather and topography were only part of their challenge.
40:19All their structures had to survive the frequent earthquakes
40:23that strike this volatile region.
40:27Recent natural disasters in Peru can give us a feel
40:30for what confronted the Incas 500 years ago.
40:34I'm back on the road with Lucio to show you what I mean.
40:38We're travelling north-west to the tragic market town of Yungay.
40:48En route, we encounter a colourful roadblock, a fiesta.
40:53In the Andes, they're a frequent and raucous celebration of life.
41:04On Sunday, the 31st of May, 1970,
41:08Yungay was celebrating an unusual fiesta of its own.
41:12It was the first day of the Mexico World Cup finals
41:15and Peru had qualified.
41:21Yungay sprawled in the shadow of Huascaran.
41:24At nearly 7,000 metres, the highest peak in all the Peruvian Andes.
41:37That afternoon, the Andes was in the middle of a storm.
41:42That afternoon, tragedy struck Yungay.
41:45A massive earthquake shook the central part of Peru.
41:49Measuring 7.8 on the Richter scale,
41:52it was the equivalent power of 400 Hiroshima atomic bombs.
41:57The quake caused death and devastation in many cities.
42:06In Yungay, however, the worst was yet to come.
42:09The earthquake had triggered an enormous landslide up there in Huascaran.
42:14The slide took just three minutes to travel 18 kilometres from up there to Yungay,
42:20covering the town in a layer of rock, ice and mud 70 metres deep.
42:26According to official figures, 13,000 people were buried beneath my feet.
42:3113,000 people were buried beneath my feet.
42:38This satellite image shows Yungay before the earthquake.
42:45And this after.
42:47The town submerged under the landslide's white mass.
42:55This may look like a rock, but it's the top of a church spire.
42:59All that emerges from the now solid layer of mountain debris.
43:05This is what a bus looks like when it's crushed together by a landslide.
43:15On Huascaran, you can still see the scar
43:18where 50 million cubic metres of the mountain just sheared off.
43:30There were a few survivors.
43:33One small group had been visiting the local cemetery on this hill.
43:41What happened here was the worst earthquake-triggered landslide in recorded history.
43:50Earthquakes occur because the planet is covered in a patchwork of huge plates
43:55floating on a plasticky interior.
43:59Two of these plates, the Nazca and the South American,
44:03have thrown up the Andes as they've crashed together deep below us.
44:09Peru suffers from serious earthquakes every few years.
44:12They're caused by that Nazca plate pushing underneath the South American one,
44:16which thrusts up the mountains.
44:18As the plates collide, friction makes them stick.
44:21The pressure builds until suddenly they slip.
44:24The result is earthquakes, landslides and terrible devastation.
44:34The Incas knew all about the geological risks of the region.
44:38And while there's little they could have done about a mountain shearing off,
44:42they had to design buildings capable of withstanding massive quakes.
44:47There's evidence of how they achieved this back here,
44:51overlooking the Inca village of Ollantaytambo.
44:54These monumental stones were in part an Inca response
44:58to the violent seismic activity that shook their empire.
45:01They're incredibly well carved.
45:03Look, you can't even slip a coin or a piece of paper in between them.
45:07And there's no need of mortar.
45:09If you look down here, as you go up the wall, the stones get smaller.
45:13And if you look at where the joints meet,
45:15look, you can see they're staggered.
45:17They're not straight.
45:19It's like an interlocking jigsaw that minimises lines of weakness.
45:22And all of this helps to make this construction earthquake-proof.
45:28Windows, doorways and most walls slope inwards
45:32to make them stronger and more flexible when a quake strikes.
45:36But how do they carve out these walls?
45:39And how did they transport those huge stone blocks without a wheel?
45:44Apparently, there's some clues at the bottom of this ramp.
45:50And on hand to tell me more, historian Peter Frost.
45:53Hi, Peter. So what have we got here?
45:55It's a tired stone, as they call them here.
45:57I'm sure it is. What's a tired stone?
45:59Well, it's a stone that doesn't move.
46:01It's a stone that doesn't move.
46:03It's a stone that doesn't move.
46:05It's a stone that doesn't move.
46:07So what's a tired stone?
46:09Well, it's a stone that never made it from the quarries to the construction site.
46:13So does this give us an idea on how it was carved then?
46:16Yeah. We have to get on the top really to see what they've been doing here.
46:19Hang on.
46:23See these pot marks all over the surface of the stone?
46:26Yes. I mean, to me, these aren't natural.
46:28No. Those are the telltale signs of Inca use of hammer stones.
46:32This is an Inca hammer stone. It's made of hematite.
46:34Oh, I know it. Well, it's heavy, yeah.
46:36It's heavy, very hard, and very effective in carving away the surface of a softer stone.
46:42So what, they would just peck, peck, peck, rock on rock?
46:44That's it.
46:46It must have taken them absolutely ages.
46:48Well, not as much as you might think, actually,
46:50because there are people who've duplicated this work in Inca quarries
46:54that, in fact, it doesn't take as long as you'd imagine.
46:57I mean, this is enormous. So how did they actually transport it?
47:01They were coming across open country here from the quarries,
47:05and if you have enough people and enough rope, you can do it.
47:08And the Incas did have this huge reserve of manpower.
47:12They never seemed to be short of people.
47:14Couldn't they have used cattle or something to just pull it off or something?
47:17They didn't have cattle.
47:18They didn't have cattle.
47:19Well, listen, Peter, I'm going to give you back your hammer stone.
47:22I'm going to say thank you once again.
47:24That was great. That was very useful.
47:26I'm just going to finish carving this stone.
47:28Are you? Well, don't ask me to drag it up the hill.
47:30All right.
47:31Bye.
47:33Although the Incas had been dealt a truly harsh hand by geology,
47:37they were ingenious enough to fight back and thrive.
47:41But theirs is a story with a bitter twist.
47:45To show you what it was, I've come to the Inca capital, Cusco.
47:57This was the centre of Inca power and wealth.
48:00From here, the Inca emperors,
48:02believed to be the divine descendants of the sun,
48:05ruled their vast empire.
48:11Cusco is a bustling modern city now,
48:13but there are still traces of its glory under the Incas.
48:19Some streets are flanked by extraordinary foundation walls
48:22that have withstood centuries of earthquakes.
48:30This proud Inca empire was built supremely
48:33to cope with the challenges of its geological setting.
48:36Here were a people who knew how to farm the mountains,
48:39administer a rugged terrain
48:41and build magnificent roads, storehouses and buildings
48:45to withstand the shaking of the earth.
48:47They might have thought, what could possibly go wrong?
48:55In the end, of course, their undoing was down to a product
48:58of the giant geological cooking pot beneath their feet.
49:02Gold.
49:04It's hard to believe that these shiny, precious trinkets
49:07started off as a metal-rich stew,
49:10injected by superheated waters up into the hearts of mountains
49:15and later liberated by eroding rivers
49:18to form particles or nuggets of pure gold.
49:29The Incas loved gold, not as money,
49:33but for making beautiful objects.
49:35For them, it only took on value
49:37when crafted into ceremonial jewellery,
49:40figurines and adornments for tombs and temples.
49:49In 1532, Francisco Pizarro and his Spanish conquistadors
49:54arrived in Peru.
49:56And they came in search of gold.
50:02While the Incas had mastered their landscape,
50:05they were unprepared for the threat of the Spanish.
50:08Within a few years, they were a conquered people.
50:11Their glory extinguished.
50:14But one extraordinary treasure escaped the Spanish
50:17and it's not here in Cusco.
50:20The climax of my geological journey
50:22is an archaeological treasure
50:24that lies at the end of a three-day hike,
50:26or, from Cusco, a four-hour train ride.
50:31Recent discoveries at Machu Picchu
50:33have given us a new insight
50:35into the true nature of the Inca relationship with the mountains.
50:40All the trains go to Machu Picchu here.
50:43Archaeologist and explorer Dr Gary Ziegler is coming with me.
50:46Well, this is quite a crowd, isn't it?
50:48Yeah, it's amazing.
50:49Something like 500,000, I understand, go to Machu Picchu.
50:52500,000? Can you believe that?
50:54That's a year.
50:55In the last few years, Gary's expeditions
50:58have uncovered two major Inca sites once hidden in this region.
51:03He's a real-life Indiana Jones.
51:06He's a real-life Indiana Jones.
51:09It was here, 85 years ago,
51:11that another American made one of the finds of the century.
51:15So tell me about the discovery of Machu Picchu.
51:17Oh, it's a wonderful story.
51:19Hiram Bingham, an intrepid American explorer in the year 1911
51:24was travelling down the Urubamba River Valley looking for ruins.
51:28And he stopped at the Urubamba River Valley
51:31to look for ruins,
51:33and he found the ruins.
51:35Looking for ruins.
51:37And he stopped at a small place there,
51:40what's below Machu Picchu now.
51:42There was a family actually farming
51:45on one of the terraces at Machu Picchu.
51:48He offered a reward.
51:49They took him up, and he found the site.
51:51So it's easy.
51:52Piece of cake.
51:54So how do you do it today?
51:56Well, we tried high-tech.
51:57We tried satellite imagery.
51:59We tried thermal imaging from an aircraft.
52:03But it's all come down to swinging a machete on the ground.
52:06Old style.
52:07That's right.
52:09Gary is going to show me something in Machu Picchu
52:12that these tourists won't find in their guidebooks.
52:19There's something hidden in its design,
52:22an ancient geological code that's only now being unlocked.
52:34Machu Picchu
52:48High above the Urubamba River,
52:50deep in cloud forest,
52:52lies breathtaking Machu Picchu.
53:04Wow. Look at this.
53:07Is this not fantastic?
53:09This is a classic view, isn't it?
53:11It is.
53:12The clouds sweeping it over.
53:14It really captures the mystery and the romance of it.
53:18Can you imagine what this must have looked like in Inca times?
53:21I haven't a clue.
53:22Imagine the thatched roofs covering everything.
53:24Imagine these walls being totally cleaned and brilliantly white.
53:27And certainly there would have been decorative plants and flowers around.
53:30It must have been completely ablaze with colour.
53:33Undoubtedly.
53:39Until recently,
53:40the importance of the mountains that embrace Machu Picchu
53:44has not been fully appreciated.
53:46It's these peaks that are the key to deciphering the Inca's geological code.
53:54Everywhere Gary takes me, he points out carved rocks.
53:57He's picking out what are called replica stones,
54:00designed to echo the shapes of the mountains behind them.
54:09Is that a series of replica stones everywhere?
54:15Well, look at this, Ian.
54:16This is one of the best replication stones I know of at Machu Picchu.
54:21Now, look carefully at the shape of the rock.
54:23Look at the two arms coming off of it.
54:25And it seems to closely represent the mountain in the background,
54:29which is Cerro Llanotin.
54:31And that sloping bit at the back is the sloping back wall of the peak.
54:35Exactly.
54:36It's as close to the canyon on the right as you can get.
54:39That's amazing.
54:40It's amazing.
54:41So they certainly intended to make a replication
54:43of the mountain in the background here.
54:45What this suggests, then,
54:46is that Llanotin was something important in mountain worship
54:50to at least this part of the site and people passing by here.
54:54And so they took the boulder, they enshrined or made a roadside shrine
54:58out of a replica of the peak behind.
55:04Inca religion venerated not only mountains
55:07but boulders and rock formations.
55:12Their architecture sought to work in harmony with the surrounding stone.
55:16And here's this great carved stairway.
55:18This is all rock?
55:19All solid rock.
55:21Carved out of the native bedrock.
55:25As we come up on top of the highest point here,
55:28there's something I'd like to show you that's fantastic.
55:36Look across the plaza
55:38and look at this wonderful example of native rock blended into the construction.
55:43It's beautiful.
55:44That's probably one of the finest examples of Inca architecture
55:47in the entire Inca empire.
55:49Fantastic how they've blended that in there.
55:55Since Hiram Bingham's rediscovery of Machu Picchu,
55:59sun worship and solstice ritual
56:01were believed to be the main religious rites here.
56:04After all, we know the emperor claimed descent and authority from the sun god.
56:09But the new focus on the site's geology has changed that.
56:14Now Machu Picchu appears more like an altar to the rocks.
56:19Ian, here we are.
56:20This is my favourite place
56:22and probably the most sacred point and most important point of Machu Picchu.
56:27It's interesting that Bingham identified this or named it the Entiwantana.
56:32Entiwantana means in some sort of description of a hitching post of the sun.
56:37Others have called it a sundial.
56:39Of course, like most of what Hiram Bingham established in his conclusions
56:44has since been reinterpreted.
56:46Right. It was a bit too imaginative, wasn't it?
56:48Exactly.
56:49We now think of the stone as more of a focal point.
56:52It seems to be that it's a replication of Huayna Picchu mountain in the background.
56:56And because it's the highest point here in Machu Picchu,
56:59it represents Huayna Picchu as the protective deity of Machu Picchu, the city.
57:05It looks obvious.
57:06But also, it's just a beautiful rock, isn't it?
57:09It's exquisitely carved. It's like a piece of art.
57:12It certainly is. It's Inca art.
57:14Inca art, yeah.
57:15Geology and art.
57:17Fabulous.
57:20MUSIC
57:28For me, it doesn't get any better.
57:31I've learned that the Inca story is inextricably woven into the rocks.
57:36These rugged lands, the climate, the gold,
57:39all were products of geological forces
57:41that worked beneath the feet of these great people.
57:44That they built such a successful empire
57:47boils down to their deep understanding of this unique natural landscape.
57:56The secrets of Machu Picchu that have recently been revealed
58:00show that the Incas not only understood these magnificent mountains,
58:04they worshipped them in a profound and, to me, even moving way.
58:09And what I've discovered from my journey through modern Peru
58:12is that this respect and veneration for the Andes
58:15is still a vital part of life here today.
58:33Next week, Ian's in Japan
58:35for more journeys into the Ring of Fire at nine.
58:38But tonight, how the make-do and mend ethos of the war years
58:41resulted in affordable furniture all round.
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