00:07 - 00:13
it's tiring
00:08 - 00:15
the wind's blowing it's it's icy cold
00:13 - 00:18
this is so steep i don't know how they
00:15 - 00:18
got the bricks up here
00:18 - 00:22
the great wall of china
00:30 - 00:35
it's like being in the top of the world
00:35 - 00:40
endless wall endless watchtowers all the
00:38 - 00:44
way to the horizon
00:40 - 00:47
it's like nothing you could ever imagine
00:44 - 00:50
it's been studied for decades but now
00:47 - 00:53
new technology is revealing its secrets
00:50 - 00:53
like never before
00:54 - 01:02
i'm alan maca an archaeologist
00:58 - 01:02
and expert in ancient civilizations
01:02 - 01:06
and i'm going to investigate china's
01:04 - 01:10
distant past
01:06 - 01:10
from a whole new perspective
01:13 - 01:20
today state of the art satellites see
01:16 - 01:20
the world in stunning detail
01:21 - 01:26
and reveal hidden archaeology enabling
01:24 - 01:30
us to recreate a lost
01:26 - 01:31
ancient world invisible to the naked eye
01:31 - 01:36
working alongside leading chinese
01:36 - 01:40
my team and i will travel to some of the
01:38 - 01:43
country's most remote and incredible
01:43 - 01:46
and with cutting-edge science
01:46 - 01:55
previously unknown cultures lost
01:49 - 01:55
cities and devastating cataclysms
01:56 - 02:09
this is ancient china as you've never
01:59 - 02:09
seen it before
02:16 - 02:23
just outside china's capital beijing
02:21 - 02:26
10 million people a year come to marvel
02:23 - 02:26
at the great wall
02:26 - 02:31
this is the biggest man-made structure
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on the planet
02:31 - 02:37
but the only way to really see just how
02:37 - 02:42
is from 500 miles above the earth
02:42 - 02:46
using satellite images i'm going to
02:44 - 02:51
track the great wall across
02:46 - 02:51
towering mountains and remote desert
02:52 - 02:56
exploring massive defenses they will
02:56 - 03:01
raining down fire and arrows from above
02:59 - 03:04
meeting archaeologists as they unearth
03:01 - 03:05
its ancient past oh this is amazing
03:04 - 03:09
you've literally
03:05 - 03:13
just found these and revealing its long
03:09 - 03:13
hidden secrets looks really cool
03:15 - 03:18
to discover if this great monument could
03:18 - 03:25
bigger and far older
03:21 - 03:25
than we'd ever thought before
03:31 - 03:35
i'm starting my mission 70 miles north
03:35 - 03:40
in the rugged mountains of jin chandling
03:40 - 03:46
at a part of the wall that's remained
03:41 - 03:49
unchanged for hundreds of years
03:49 - 03:55
you see pictures of the great wall and
03:51 - 03:55
tourist books but this is something else
03:58 - 04:03
out here in jin chandling satellite data
04:01 - 04:06
shows how the wall crosses seemingly
04:03 - 04:06
impossible peaks
04:07 - 04:12
and every few hundred feet
04:12 - 04:16
huge stone structures
04:17 - 04:21
on the ground these towers reveal
04:19 - 04:25
meticulous engineering
04:25 - 04:31
look at how beautiful this is really
04:28 - 04:36
formal arches here
04:31 - 04:39
lots of space windows all the way around
04:36 - 04:40
you have a 360 degree view over the
04:40 - 04:43
it's incredible
04:43 - 04:49
this is just one of around 25 000
04:46 - 04:55
watch towers built by the ming dynasty
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who ruled china from 1368 to 1644.
04:55 - 05:01
between the towers
04:57 - 05:03
ingenious defenses i'm seeing these
05:01 - 05:06
strange holes along the wall that
05:03 - 05:06
open to the outside what they would have
05:06 - 05:09
is taken about a five pound rock
05:08 - 05:12
hollowed it out
05:09 - 05:12
stuffed it with gunpowder put a wick in
05:12 - 05:17
and literally just rolled it out the
05:17 - 05:20
no more invaders
05:21 - 05:24
the ming went to these extraordinary
05:23 - 05:27
lengths to combat
05:24 - 05:29
a mortal enemy
05:29 - 05:35
from space satellites reveal vast
05:32 - 05:38
grasslands to the north of the wall
05:35 - 05:38
wild enough today in the days of the
05:38 - 05:43
this was home to tribes of nomadic
05:50 - 05:53
these fearsome warriors had been
05:51 - 05:56
attacking and pillaging china for
05:58 - 06:06
the ming built the great wall to keep
06:00 - 06:09
them out now
06:06 - 06:11
600 years later chinese experts are
06:09 - 06:21
using science and technology
06:11 - 06:21
to reveal its secrets
06:23 - 06:26
everywhere i look i see watchtowers on
06:26 - 06:31
the mountaintops near a remote section
06:31 - 06:37
this view is unbelievable canadian
06:35 - 06:38
archaeologist sarah klassen
06:37 - 06:42
is on her way to meet one of the teams
06:38 - 06:46
carrying out this groundbreaking work
06:46 - 06:50
lee jia and professor zhang from tianjin
06:50 - 06:54
are using drone data to create a 3d
06:53 - 06:58
model of the entire
06:54 - 06:58
ming dynasty wall it's the most complete
06:58 - 07:02
ever attempted we have covered two
07:02 - 07:05
one hundred kilometers along the
07:04 - 07:08
mingarit wall
07:05 - 07:13
we still have two thousand five hundred
07:08 - 07:14
kilometers to cover it's a huge job
07:14 - 07:18
without this technology doing something
07:16 - 07:19
like this would not be possible
07:18 - 07:21
just look at the landscape you'd have to
07:19 - 07:23
scale up all of those cliffs
07:21 - 07:25
and map all of these features it would
07:23 - 07:31
take decades if it would even be
07:25 - 07:33
possible at all
07:31 - 07:34
the new scans reveal the incredible
07:33 - 07:38
achievements of the ming
07:34 - 07:41
in some of china's most extreme terrain
07:38 - 07:41
even on completely impassable ridges
07:41 - 07:47
still succeeded in erecting towers can
07:44 - 07:47
you show me what you've done here
07:47 - 07:52
you can see there is the run part here
07:50 - 07:55
very close to the cliff
07:52 - 07:56
they want to stop all the enemies and a
07:56 - 08:00
parts of the grid wall follow the reach
08:01 - 08:07
and within the scans
08:04 - 08:10
new discoveries
08:10 - 08:14
li has spotted mysterious openings along
08:13 - 08:16
the base of the wall
08:16 - 08:20
using his data i'm heading 120 miles
08:20 - 08:22
to investigate
08:24 - 08:27
look at this rugged landscape and check
08:26 - 08:28
out this ridge
08:27 - 08:30
see the watch towers up on the ridge
08:28 - 08:32
that's where the wall is
08:30 - 08:33
so the wall is snaking all the way down
08:32 - 08:40
to the saddle over here
08:33 - 08:43
and that's where i want to go
08:40 - 08:44
the wall here is crumbled away but
08:43 - 08:48
originally it would have stood as tall
08:44 - 08:48
as a three-story house
08:50 - 08:55
wow can you imagine
08:53 - 08:57
a solid wall all the way down from this
08:57 - 09:02
and all of a sudden there's this door
09:00 - 09:04
clear through the daylight
09:02 - 09:06
it's completely baffling why would a
09:04 - 09:08
defensive wall have a doorway
09:06 - 09:11
running right through it
09:12 - 09:18
yeah this is a pretty small
09:15 - 09:19
compact space right now but without all
09:18 - 09:20
this rubble here this would have been
09:20 - 09:24
of a person would have just walked right
09:22 - 09:26
through here the crazy thing is
09:24 - 09:27
you know this is not some random hole in
09:27 - 09:31
this thing is incredibly well built look
09:29 - 09:33
at all these bricks this is a perfect
09:31 - 09:35
beautifully made arch
09:33 - 09:37
so this was planned and the question is
09:38 - 09:44
lee joe has found more than 50 of these
09:41 - 09:46
doors along this part of the wall
09:44 - 09:51
and it's thought that could be used by
09:46 - 09:54
scouts sent out to spy on the enemy
09:51 - 09:57
but the data revealing something else
09:54 - 09:59
the ragged edge revealed in this scan
09:57 - 10:01
isn't a decayed doorway
09:59 - 10:03
but the entrance to a hidden tunnel that
10:01 - 10:07
was once bricked up
10:03 - 10:07
before being smashed open
10:07 - 10:13
looks really cool the doctor
10:11 - 10:15
the hidden door somebody called the
10:15 - 10:19
this new discovery is completely
10:17 - 10:22
different from any of the other openings
10:19 - 10:24
lija has found
10:22 - 10:25
potentially a way of launching a sudden
10:27 - 10:33
it seems this healing door is originally
10:30 - 10:37
sealed by normal wreaks
10:33 - 10:41
soldiers inside then break the surface
10:37 - 10:41
and go outside and land should attack
10:43 - 10:48
smashing open this thin layer of bricks
10:46 - 10:51
allowed the ming forces to ambush the
10:52 - 11:00
before lee jo's discovery experts had no
10:54 - 11:02
idea these hidden tunnels even existed
11:00 - 11:04
it's an incredible find we cannot
11:02 - 11:15
imagine that before
11:04 - 11:17
you know all this makes me astonish
11:15 - 11:18
the latest technology is revealing that
11:18 - 11:22
far more than a simple barrier
11:23 - 11:32
it's a complex military system
11:28 - 11:32
the big question is just how far does it
11:35 - 11:40
using satellite images we can
11:38 - 11:44
reconstruct how the ming wall extends
11:40 - 11:47
far to the west from mountain ranges
11:44 - 11:48
through wild grasslands and into barren
11:48 - 11:52
right to its end where the ming stopped
11:52 - 11:57
here at the very furthest reaches of
11:54 - 12:00
their empire
11:57 - 12:04
a huge construction far greater than any
12:00 - 12:07
of the thousands of towers along the way
12:04 - 12:10
what is it and what was it for
12:07 - 12:11
to find out i'm going to follow the wall
12:11 - 12:25
flung corner of western china
12:34 - 12:38
i'm investigating the secrets of one of
12:36 - 12:40
the world's greatest
12:38 - 12:43
ancient icons
12:43 - 12:46
using satellite data i've tracked the
12:46 - 12:50
all the way from the mountains east of
12:50 - 12:56
to the gobi desert a 500 000
12:53 - 12:58
square mile expanse in the far northwest
13:00 - 13:05
just over here i can see sections of the
13:05 - 13:08
the feat of engineering required to
13:06 - 13:11
build something so far out here
13:08 - 13:12
in just this barren desolate environment
13:11 - 13:15
just kind of
13:12 - 13:15
boggles the mind
13:19 - 13:26
after hours following the wall something
13:22 - 13:26
massive emerges from the desert haze
13:33 - 13:36
a mighty fortress
13:37 - 13:41
today the modern city of jayaguan is
13:41 - 13:44
but 600 years ago this fortress would
13:43 - 13:48
have stood alone
13:44 - 13:50
in a desolate wilderness
13:48 - 13:51
i never imagined i'd ever see something
13:50 - 13:54
like this all the way out here in
13:51 - 13:55
western china
13:54 - 13:59
the great wall terminates in the
13:55 - 14:02
mountains just a few miles south of here
13:59 - 14:03
making this incredible structure the
14:03 - 14:08
final gateway the last fortress
14:06 - 14:09
at the furthest edge of the ming
14:08 - 14:12
dynasty's vast
14:12 - 14:16
look at how massive this is this rivals
14:16 - 14:21
any gate or battlement anywhere in the
14:18 - 14:21
world at this time
14:23 - 14:27
here you really get a sense of the
14:25 - 14:32
ambition the engineering
14:27 - 14:32
and the immense power of the ming
14:32 - 14:40
a deep moat walls up to 36 feet high
14:37 - 14:44
and watch towers on every corner form
14:40 - 14:46
three layers of defense and even if the
14:44 - 14:48
enemy does make it inside there are
14:46 - 14:51
traps designed to create
14:48 - 14:51
devastating kill zones
14:55 - 15:01
you walk into this courtyard
14:58 - 15:02
and if you're an invading army they can
15:01 - 15:04
close those doors
15:02 - 15:07
close those iron doors there and you're
15:04 - 15:09
trapped here and all of a sudden
15:07 - 15:13
they will just start raining down firing
15:09 - 15:13
arrows from above
15:15 - 15:20
and your invading force is doomed this
15:17 - 15:22
is an ingenious military strategy
15:20 - 15:27
all set and fixed in the design of this
15:22 - 15:27
incredible fortress
15:28 - 15:33
it's massive but also meticulously built
15:35 - 15:38
the precision of construction here is
15:38 - 15:41
you know the emperor demanded that and
15:39 - 15:43
there's this legend that says
15:41 - 15:45
the architect told the emperor he said i
15:43 - 15:47
can tell you the exact number of bricks
15:45 - 15:48
it will take to build this fortress he
15:47 - 15:51
said it will be
15:51 - 15:54
and incredibly at the end of
15:52 - 15:56
construction there was just one brick
15:56 - 15:59
and that brick is set over there on that
15:58 - 16:01
little ledge
15:59 - 16:05
as a kind of mini monument to the
16:01 - 16:05
incredible precision design of this
16:10 - 16:15
its position right at the end of the
16:12 - 16:15
ming dynasty's great wall earned it the
16:15 - 16:22
the first and greatest pass under heaven
16:19 - 16:25
but this fortress is just one small part
16:22 - 16:25
of a mega structure like nothing else on
16:29 - 16:34
just one end of their great wall of
16:45 - 16:50
until we had images from space experts
16:48 - 16:51
didn't know how massive the ming
16:50 - 16:54
dynasty's great wall
16:55 - 16:59
but now chinese experts have calculated
16:58 - 17:03
it's five and a half
16:59 - 17:06
thousand miles long that's over 1500
17:03 - 17:08
miles more than previously thought
17:06 - 17:11
and long enough to stretch from new york
17:08 - 17:16
to los angeles and all the way back
17:20 - 17:23
but new technology is also unearthing
17:23 - 17:28
that take us beyond the great empire of
17:28 - 17:32
1200 miles away sarah has set up a base
17:32 - 17:36
shadow of the great wall we know the
17:34 - 17:39
fortress of jiuguan
17:36 - 17:40
marks the end of the ming wall but the
17:39 - 17:47
satellite data
17:40 - 17:50
reveals something else oh wow
17:50 - 17:54
chinese experts have told sarah about
17:53 - 17:57
another section
17:54 - 17:59
even further into the desert if i zoom
17:57 - 18:01
in on the satellite imagery i can see
17:59 - 18:03
that this part of the wall
18:01 - 18:04
is much more eroded than other parts of
18:04 - 18:07
so i might suggest that it's older than
18:06 - 18:08
the parts of the wall built during the
18:07 - 18:11
ming dynasty
18:11 - 18:17
this wall stretches far beyond the ming
18:14 - 18:20
fortress continuing west for
18:17 - 18:22
hundreds of miles the wall is completely
18:20 - 18:24
straight in the middle of this desert
18:22 - 18:25
there's absolutely nothing else around
18:25 - 18:30
can't imagine why they would need to
18:27 - 18:33
build a wall here
18:30 - 18:36
so what's going on i'm heading west in
18:33 - 18:39
search of answers
18:36 - 18:41
i want to know just how old is this wall
18:41 - 18:45
where does it go and if the ming didn't
19:04 - 19:11
i'm now more than 230 miles west of the
19:07 - 19:11
fortress of jiuguan
19:17 - 19:21
here in the kumtag desert it's one of
19:20 - 19:22
the harshest environments i've ever been
19:22 - 19:25
you know very little grows here the
19:24 - 19:29
temperatures are
19:25 - 19:29
literally below freezing
19:29 - 19:33
it's a hell of a place to imagine
19:30 - 19:33
finding archaeology
19:35 - 19:38
sarah's guiding me to faint traces of
19:37 - 19:41
what looks like an even
19:38 - 19:42
older wall that she spotted on the
19:41 - 19:46
satellite data
19:46 - 19:53
if i get up here i think i can get my
19:47 - 19:53
first glimpse
19:58 - 20:02
wow this is cool and it's not exactly
20:01 - 20:04
what i expected
20:04 - 20:07
and it looks kind of primitive
20:08 - 20:12
want to see more line get up closer
20:15 - 20:20
here in the middle of nowhere a stretch
20:18 - 20:21
of ancient wall
20:20 - 20:23
and it looks very different from
20:21 - 20:26
anything i've seen so far
20:27 - 20:30
this is a very distinctive kind of
20:30 - 20:36
we have rammed earth packed down
20:34 - 20:37
with a reed foundation these are reeds
20:36 - 20:40
this is actually a
20:37 - 20:41
you know a type of thick grass pressed
20:40 - 20:42
in there to serve as a foundation to
20:41 - 20:46
hold the wall
20:42 - 20:48
stable this framework is an ingenious
20:46 - 20:51
way of building even with the desert's
20:48 - 20:54
loose sand and gravel
20:51 - 20:56
but if the ming didn't build this then
20:57 - 21:02
to find out i'm meeting zhang joon min
21:00 - 21:04
the head of a team from the gansu
21:02 - 21:07
institute of relics and archaeology
21:04 - 21:07
who are digging for answers
21:08 - 21:12
wow this is so cool tell me what you
21:12 - 21:19
these are two arrowheads we found nearby
21:16 - 21:22
one is bronze and one is iron
21:19 - 21:25
you can see it's still sharp i've never
21:22 - 21:27
seen this shape to an arrowhead before
21:25 - 21:28
you know where it's it's basically
21:28 - 21:34
like this and it is is that common
21:32 - 21:35
i found lots of these along the wall in
21:35 - 21:44
these arrowheads are very typical of the
21:44 - 21:50
fifteen hundred years before the ming
21:48 - 21:51
before the roman empire formed in the
21:51 - 21:59
and cleopatra ruled ancient egypt
21:56 - 22:01
the han dynasty rose to power
22:01 - 22:09
they oversaw a golden age of art
22:04 - 22:09
culture and economic prosperity
22:10 - 22:13
they're so well preserved i'm just
22:11 - 22:17
amazed look at that edge
22:13 - 22:21
it's just incredible the form is just so
22:17 - 22:26
clear and beautiful these tiny
22:21 - 22:29
arrowheads reveal something momentous
22:26 - 22:31
that the wall here is more than 2 000
22:34 - 22:42
it's an even earlier great wall of china
22:38 - 22:45
that once stretched for over 6 000 miles
22:45 - 22:49
much of the famous ming dynasty wall was
22:48 - 22:55
simply built
22:49 - 22:55
right on top 1500 years later
22:56 - 23:00
battered by desert winds for over two
23:00 - 23:03
what remains of this ancient stretch of
23:03 - 23:06
are just fragments of what was once a
23:06 - 23:11
barrier it's kind of hard just looking
23:09 - 23:13
at these ruined sections of the wall
23:11 - 23:15
to get a sense of what it looked like
23:13 - 23:17
originally so using historical sources
23:15 - 23:19
and archaeological evidence we've made
23:17 - 23:21
this pretty phenomenal digital
23:19 - 23:26
reconstruction of what the wall
23:21 - 23:26
might have looked like it's just amazing
23:29 - 23:36
when it was first built the wall would
23:32 - 23:38
have stood up to 20 feet high
23:36 - 23:40
this thing was enormous i can only
23:38 - 23:42
imagine being part of a
23:40 - 23:44
an invading nomad army and coming up
23:42 - 23:46
against this wall
23:44 - 23:48
and thinking you know maybe it's better
23:46 - 23:50
to just go home because
23:48 - 23:53
this was formidable
24:00 - 24:05
then another discovery just unearthed
24:04 - 24:07
from the desert sands
24:05 - 24:09
that suggests the wall was about more
24:07 - 24:12
than just defending
24:09 - 24:12
chinese territory
24:13 - 24:18
we found this coin nearby it's a wooju
24:20 - 24:24
oh this is amazing you've literally
24:22 - 24:29
literally just found these
24:24 - 24:29
yeah it may be they were left here by
24:35 - 24:40
these merchants may have been traveling
24:37 - 24:44
along a series of ancient trade routes
24:40 - 24:44
known as the silk road
24:44 - 24:48
established by the han the silk road
24:47 - 24:51
stretched from china
24:48 - 24:53
through central asia and india to
24:51 - 24:56
modern-day turkey
24:53 - 24:59
egypt arabia and rome it brought huge
24:56 - 25:02
wealth to china and had to be defended
24:59 - 25:02
at all costs
25:03 - 25:07
so the great wall was not just about
25:05 - 25:09
protecting the empire
25:07 - 25:10
it also served to protect china's
25:09 - 25:15
gateway to this
25:10 - 25:17
vital artery of global trade
25:17 - 25:20
but there's something else intriguing
25:20 - 25:26
alongside the wall more ancient remains
25:26 - 25:31
rising from the desert a mysterious
25:28 - 25:31
eroded structure
25:35 - 25:40
my tech team ryan castner and eric lowe
25:38 - 25:42
are joining me
25:40 - 25:43
and working with experts from peking
25:43 - 25:49
we're going to investigate
25:53 - 25:58
i'm on a quest to uncover the secrets of
25:55 - 26:01
the great wall of china
26:02 - 26:05
and my tech team is working with
26:04 - 26:08
researchers ma li
26:05 - 26:09
wu yunnan and maching long from peking
26:09 - 26:12
to investigate what seems to be a
26:11 - 26:16
mysterious tower
26:12 - 26:17
built near an ancient section of wall so
26:16 - 26:17
they're flying the drone now we're going
26:17 - 26:21
first do sort of a lawn mower pattern
26:19 - 26:24
over the top to get the aerial view
26:21 - 26:26
of the tower there the drone takes
26:24 - 26:28
hundreds of images of the structure
26:26 - 26:32
which will combine to make a detailed
26:28 - 26:32
three-dimensional model
26:33 - 26:37
after that the team will scan a four
26:35 - 26:40
mile section of the wall for traces of
26:37 - 26:42
any more remains
26:40 - 26:43
using a drone to be able to fly will
26:42 - 26:44
save us a lot of time the drone can go a
26:43 - 26:47
lot faster than
26:44 - 26:50
we can on foot
26:50 - 26:55
hours of flight and 1500
26:53 - 26:59
individual pictures later
26:59 - 27:02
hey guys come on in and i've come to
27:01 - 27:04
check out the results with
27:02 - 27:05
archaeologists and leading han wall
27:05 - 27:09
yang jun who'll help us interpret our
27:09 - 27:13
all right guys so show me what you got
27:11 - 27:14
all right so to give you some context
27:13 - 27:16
you can see the wall from from the
27:14 - 27:17
satellite image very clearly if you look
27:16 - 27:20
it's a nice
27:17 - 27:22
linear feature here but switching to the
27:20 - 27:24
3d elevation model
27:22 - 27:26
reveals details not visible in the
27:24 - 27:27
satellite imagery
27:26 - 27:29
so if we look and actually in this spot
27:27 - 27:31
here um right where it bends there
27:29 - 27:34
there seems to be a clear clear bump
27:31 - 27:36
there that doesn't seem to be natural
27:34 - 27:38
you can see in the elevation model the
27:36 - 27:40
redder it is the taller it is
27:38 - 27:41
that's a five or six meter tall mound
27:40 - 27:43
there it seems to make a whole lot of
27:41 - 27:43
sense to us that that would be another
27:43 - 27:47
because it turns at an angle it cuts
27:45 - 27:48
back south exactly
27:47 - 27:50
exactly so that would be a natural spot
27:48 - 27:53
where you'd want to look out to see
27:50 - 27:55
on all sides where everything was
27:53 - 27:59
the structure's height and strategic
27:55 - 27:59
position suggests it may have been a
28:03 - 28:07
then ryan spots something totally
28:07 - 28:11
you can see a clear structure another
28:08 - 28:14
tower that was behind the wall
28:11 - 28:15
basically on top of a hill this is
28:14 - 28:19
really interesting
28:15 - 28:19
did they build towers off the wall
28:20 - 28:24
from our research we found most of the
28:24 - 28:31
were along the wall but there are a few
28:27 - 28:31
that are outside
28:32 - 28:36
it's bizarre some of these towers are
28:34 - 28:40
deep in enemy territory
28:36 - 28:42
miles beyond the wall were they really
28:40 - 28:44
just simple watchtowers
28:42 - 28:47
or could there be more going on here
28:47 - 28:52
600 miles away in a vault at the gansu
28:50 - 28:54
jianju museum
28:52 - 28:56
are ancient relics which could hold the
28:56 - 29:02
oh research director
29:00 - 29:03
sao song li has agreed to show our
29:02 - 29:08
historian dr
29:03 - 29:08
ciao hue chenille these amazing finds
29:09 - 29:15
these are wooden slips they're
29:12 - 29:16
about the length of a ruler the wood
29:15 - 29:20
looks well preserved
29:16 - 29:24
on it you have these writings in ink
29:20 - 29:24
very fine writing buried in the desert
29:24 - 29:29
thousand years these slips were
29:27 - 29:31
unearthed in what was once the office of
29:29 - 29:34
a military commander
29:31 - 29:35
and they contain instructions for
29:35 - 29:39
stationed at the towers okay they're
29:38 - 29:41
really hard to make out
29:39 - 29:42
oh first of all on the very top there is
29:42 - 29:45
that tells you that's the beginning of
29:44 - 29:46
the rules and then the first two
29:50 - 29:56
that means the huns the huns were feared
29:54 - 29:58
nomadic horsemen
29:56 - 30:01
who roamed the northern grasslands a
29:58 - 30:04
thousand years before the mongols
30:01 - 30:06
so the rule here is talking about what
30:04 - 30:10
you should do
30:06 - 30:10
when the huns come into the border
30:14 - 30:20
okay so the next characters say you must
30:17 - 30:24
raise a flag on the pole
30:20 - 30:28
rajon raising this flag
30:24 - 30:32
a marker known as a pung could only have
30:28 - 30:34
one purpose to signal other towers
30:32 - 30:38
and there are even rules for what to do
30:34 - 30:42
at night when flags can't be seen
30:38 - 30:42
by night start a fire on top of a tower
30:45 - 30:52
and do not put it out until the morning
30:50 - 30:54
all towers that see this light should
30:52 - 30:55
also light and it goes all the way down
30:54 - 30:57
the defense line
30:55 - 30:58
until it reaches the commandery where
30:57 - 31:02
the soldiers are
31:02 - 31:07
said and the slips even contain
31:05 - 31:11
instructions on how to signal
31:07 - 31:11
how many enemies were attacking
31:12 - 31:15
so let's say you have more than a
31:13 - 31:16
thousand huns and that's what they've
31:16 - 31:20
there's a very specific signal that they
31:20 - 31:23
so that without words the commander
31:23 - 31:26
would know that
31:23 - 31:32
there are a thousand rides coming
31:26 - 31:34
towards us this
31:32 - 31:36
tells us the towers we've mapped in the
31:34 - 31:39
desert including those
31:36 - 31:41
deep in enemy territory are not simple
31:41 - 31:47
they're beacon towers part of a complex
31:44 - 31:47
early warning system
31:50 - 31:54
using our drone data we can now
31:52 - 31:56
reconstruct a complete
31:54 - 31:58
3d model of what they may have looked
31:58 - 32:04
built over two years ago they were made
32:00 - 32:07
of rammed earth clad and plaster
32:04 - 32:11
and stood up to 26 feet high with
32:07 - 32:11
platforms on top where the fires were
32:14 - 32:18
and thanks to the incredible insights
32:16 - 32:21
revealed in the wooden slips
32:18 - 32:24
we now know that these towers formed a
32:21 - 32:26
sophisticated communication system
32:24 - 32:27
designed to provide early warning of an
32:27 - 32:42
and pass it for hundreds of miles along
32:44 - 32:49
what the han created is remarkable
32:47 - 32:53
but were they the first to build a
32:49 - 32:57
defensive wall to protect their empire
32:53 - 33:00
to trace the wall back to its very roots
32:57 - 33:01
i need to travel even further back in
33:01 - 33:07
to the reign of a tyrant of unrivaled
33:04 - 33:07
power and ambition
33:07 - 33:12
the man who conceived of another of
33:09 - 33:15
ancient china's greatest icons
33:15 - 33:25
the terracotta warriors
33:26 - 33:30
i'm in the city of shan
33:31 - 33:35
having traveled over a thousand miles
33:33 - 33:39
from the deserts of the far
33:35 - 33:42
northwest this was once the ancient
33:39 - 33:42
capital of china
33:43 - 33:46
i want to trace the origins of the great
33:46 - 33:53
but to do that i need to go back in time
33:49 - 33:55
to the formation of china itself
33:53 - 33:58
and explore the story of china's first
33:59 - 34:04
i'm starting out with his most famous
34:06 - 34:11
the terracotta warriors
34:15 - 34:21
i've been reading about this for years
34:18 - 34:23
and years but this is my first time here
34:21 - 34:24
and i'm telling you nothing nothing
34:23 - 34:27
prepares you
34:24 - 34:29
for this experience this is literally
34:27 - 34:32
one of the greatest achievements
34:29 - 34:35
in all of ancient civilization anywhere
34:32 - 34:35
in the world
34:36 - 34:42
more than six thousand figures
34:39 - 34:47
row upon row of soldiers and commanders
34:42 - 34:49
an entire army immortalized in clay
34:47 - 34:50
and all built for the first emperor of
34:50 - 34:53
chin shiwang di
34:54 - 34:59
from where i'm standing there's no two
34:57 - 35:01
figures that are alike
34:59 - 35:03
the uniforms are different their facial
35:01 - 35:05
expressions are different right down to
35:03 - 35:06
the mustaches
35:05 - 35:08
this tells me about the power that the
35:06 - 35:13
emperor was able to summon
35:08 - 35:13
in his lifetime as a ruler this is
35:14 - 35:17
extraordinary
35:18 - 35:25
from space we can see that the huge
35:21 - 35:28
hangar that shelters the terracotta army
35:25 - 35:31
is just one tiny part of his massive
35:28 - 35:32
mausoleum complex
35:31 - 35:34
and at its center
35:40 - 35:47
hidden within this strange looking hill
35:43 - 35:48
is the emperor's tomb it's never been
35:48 - 35:51
archaeologists don't yet know how to
35:51 - 35:55
without destroying the contents
35:55 - 36:01
but i'm meeting dr zhang wei shing
36:00 - 36:03
who's been using seismic scanning
36:03 - 36:09
to glimpse what lies beneath
36:06 - 36:09
what do you know about what's in there
36:09 - 36:14
we knew there's a huge battery chamber
36:11 - 36:17
under the earth
36:14 - 36:20
it's 160 by 140 meters in size
36:17 - 36:20
the 30 meters
36:20 - 36:27
and within that there's a huge nine
36:23 - 36:27
level platform
36:28 - 36:32
ancient texts say the tomb contains a
36:30 - 36:35
replica of the cosmos
36:32 - 36:39
with pearls as stars
36:35 - 36:43
rivers of liquid mercury
36:39 - 36:46
and even deadly booby traps
36:43 - 36:48
it sounds far-fetched but professor
36:46 - 36:55
zhang has found evidence that suggests
36:48 - 36:55
there may be some truth to the legends
37:00 - 37:04
we detected very high levels of mercury
37:04 - 37:10
so we know there is mercury inside the
37:07 - 37:13
huge burial chamber
37:17 - 37:23
these findings suggest there's truth in
37:19 - 37:25
the ancient texts
37:23 - 37:26
and that means there may also be truth
37:25 - 37:28
in what they record
37:26 - 37:31
of another of the emperor's construction
37:33 - 37:41
a huge defensive wall
37:37 - 37:43
the first great wall of china
37:41 - 37:45
though little remains today the records
37:43 - 37:51
show it stretched for nearly 2
37:45 - 37:54
000 miles across northern china
37:51 - 37:57
they also reveal the human cost of the
37:54 - 38:00
emperor's ambition
37:57 - 38:03
he forced 300 000 soldiers
38:00 - 38:04
and half a million laborers to work on
38:03 - 38:08
its construction
38:04 - 38:08
and for many it was the death sentence
38:10 - 38:15
they died of starvation or fatigue or in
38:13 - 38:18
some cases they were flogged to death
38:15 - 38:19
but it cemented emperor chinchiwandi's
38:19 - 38:22
in all of world history
38:30 - 38:33
after an incredible journey spanning
38:32 - 38:36
thousands of miles
38:33 - 38:39
and reaching far into the past i'm
38:36 - 38:42
nearing the end of my quest
38:39 - 38:45
but one intriguing mystery remains
38:42 - 38:46
did the first emperor really conjure up
38:45 - 38:49
the idea for a great wall
38:46 - 38:49
right out of thin air
38:50 - 38:54
to find the answer i need to go back
38:52 - 38:56
even further
38:54 - 38:58
to a time before his bloody rise to
38:58 - 39:18
and before the formation of china itself
39:15 - 39:21
i want to investigate one final mystery
39:18 - 39:23
surrounding the great wall of china
39:21 - 39:29
just how did the first emperor get his
39:23 - 39:29
idea to build a colossal defensive wall
39:31 - 39:35
that question has taken me 300 miles
39:33 - 39:43
north of xi'an
39:35 - 39:43
to the luis plateau
39:44 - 39:48
i'm following satellite images to
39:46 - 39:51
mysterious lines of
39:48 - 39:52
rocks and steep earth banks the remains
39:51 - 39:56
of a primitive and
39:52 - 39:58
clearly ancient wall
39:56 - 40:01
there's pieces of pottery scattered all
40:01 - 40:06
all around clues to who built it
40:04 - 40:09
i mean this piece is just commoner
40:06 - 40:12
commoner like cooking jar
40:09 - 40:13
and the designs on the outside tell me
40:12 - 40:18
this is very early
40:13 - 40:18
we're talking about pre-chin empire
40:21 - 40:27
2200 years ago at a time before the
40:24 - 40:30
first emperor came to power
40:27 - 40:32
china was divided into seven warring
40:33 - 40:36
to protect their territories each state
40:36 - 40:39
own defensive walls
40:42 - 40:47
incredibly these are the remains of a
40:45 - 40:49
wall built before the formation of china
40:49 - 40:53
this is pretty cool
40:57 - 41:02
in 221 bc the king of one of the warring
41:02 - 41:07
qin shiwang di is waging bloody war
41:10 - 41:18
he crushes all other states unites
41:13 - 41:18
china and declares himself the first
41:20 - 41:25
with his newfound power he combines the
41:23 - 41:28
warring state's existing walls
41:25 - 41:32
and builds new stretches to create
41:28 - 41:35
one huge defensive shield over 3
41:32 - 41:39
000 miles long the first
41:35 - 41:39
true great wall of china
41:41 - 41:44
his incredible construction would be
41:42 - 41:48
extended and developed
41:44 - 41:51
by the han dynasty
41:48 - 41:52
and over a thousand years later the ming
41:51 - 41:55
dynasty would take things
41:52 - 42:03
even further creating the monument we
42:08 - 42:15
the great wall was not one single thing
42:11 - 42:18
it was a mesh of many walls that span
42:15 - 42:22
huge periods of time i mean truly
42:18 - 42:22
china is defined by its walls
42:25 - 42:28
my investigation has taken us right
42:28 - 42:32
china to the edge of empire
42:37 - 42:41
i've tracked the great wall back to its
42:41 - 42:47
more than 2 200 years ago
42:47 - 42:53
and revealed how it's not one wall but
42:50 - 42:54
many that evolved over the centuries
42:53 - 42:59
into an astonishing
42:54 - 43:02
military masterpiece
42:59 - 43:05
we always knew it was big but now
43:02 - 43:07
using the latest satellite imagery and
43:05 - 43:09
cutting-edge technology
43:07 - 43:10
chinese archaeologists are revealing
43:09 - 43:13
that this world
43:10 - 43:14
icon is even greater than we ever
43:14 - 43:18
it's more than twice as long as
43:17 - 43:22
previously thought
43:18 - 43:25
spanning 13 000 miles
43:22 - 43:28
long enough to stretch halfway around
43:35 - 43:39
on this journey i've learned that the
43:36 - 43:41
great wall was as alive and dynamic
43:39 - 43:43
as the generations of people who built
43:41 - 43:44
it it's the result of
43:43 - 43:46
struggle and achievement spending more
43:44 - 43:48
than 2 000 years
43:46 - 43:50
it's not just an enduring symbol of
43:48 - 43:55
ancient china
43:50 - 43:59
it's the story of china itself
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