1
00:00:07,040 --> 00:00:10,480
Equipment wise, and weather wise,
you psychologically prepare yourself

2
00:00:10,560 --> 00:00:13,200
cos you've been planning
an expedition for two years,

3
00:00:13,280 --> 00:00:15,080
and you go there and it goes wrong.

4
00:00:15,160 --> 00:00:19,480
Sailors were actually terrified
to come to this area because
it was so dangerous.

5
00:00:19,560 --> 00:00:21,400
And ships did not return.

6
00:00:21,480 --> 00:00:25,000
Let go of the line a little bit!

7
00:00:28,440 --> 00:00:31,080
'LF.'
LF.

8
00:00:31,160 --> 00:00:33,560
Comms check. Comms check.

9
00:00:33,640 --> 00:00:36,480
He didn't hear me.
He didn't acknowledge.

10
00:00:41,400 --> 00:00:44,760
Humankind has explored
every continent on Earth.

11
00:00:44,840 --> 00:00:47,880
Climbed its tallest mountains.

12
00:00:50,280 --> 00:00:52,640
And even journeyed into space.

13
00:00:52,720 --> 00:00:54,640
'Thank you, Mr President.'

14
00:00:54,720 --> 00:00:57,400
But there's a vast swathe of
our own planet

15
00:00:57,480 --> 00:00:59,560
that has remained a mystery.

16
00:01:04,360 --> 00:01:06,200
The deep ocean.

17
00:01:06,280 --> 00:01:10,480
Stretching down over 35,000 feet
into crushing pressures,

18
00:01:10,560 --> 00:01:13,320
it's been near impossible
to reach.

19
00:01:13,400 --> 00:01:15,240
Until now.

20
00:01:17,240 --> 00:01:21,160
New engineering breakthroughs
are driving an audacious
global mission

21
00:01:21,240 --> 00:01:24,760
to dive to the deepest points
of all the five oceans,

22
00:01:24,840 --> 00:01:27,360
for the first time in history.

23
00:01:27,440 --> 00:01:30,840
These pioneers will push technology
to the limit...

24
00:01:30,920 --> 00:01:33,600
What the hell was that?
We have a leaking hatch.

25
00:01:33,680 --> 00:01:37,720
..to open up this final frontier
as never before.

26
00:01:37,800 --> 00:01:42,160
Trying to mentally put yourself
at the bottom is just mind-blowing.

27
00:01:42,240 --> 00:01:46,520
Mapping hidden landscapes,
discovering unknown lifeforms.

28
00:01:46,600 --> 00:01:48,200
What on Earth is that?

29
00:01:49,560 --> 00:01:53,240
And unlocking the secrets of
how life in the extreme deep ocean

30
00:01:53,320 --> 00:01:55,280
affects our entire planet.

31
00:02:09,080 --> 00:02:11,240
OK, good to go.
Good to go.

32
00:02:12,920 --> 00:02:16,360
Extreme explorer and ex naval
commander Victor Vescovo

33
00:02:16,440 --> 00:02:19,920
is putting his life on the line,
as well as 50 million dollars

34
00:02:20,000 --> 00:02:22,840
of his own money
to pursue his dream.

35
00:02:22,920 --> 00:02:25,320
Good boy. What little boy
or little girl

36
00:02:25,400 --> 00:02:27,760
doesn't grow up wanting to be
an explorer?

37
00:02:27,840 --> 00:02:30,360
And here I am with
a wonderful ship, a great crew,

38
00:02:30,440 --> 00:02:32,920
now the deepest submersible
in the world

39
00:02:33,000 --> 00:02:36,000
and I get to play in the ocean
with it and discover things

40
00:02:36,080 --> 00:02:39,560
that have never been seen before.
How could you not be
absolutely ecstatic?

41
00:02:40,640 --> 00:02:43,560
His mission is to travel to
each of the five oceans,

42
00:02:43,640 --> 00:02:45,560
discover their deepest point

43
00:02:45,640 --> 00:02:48,120
and unlock their unexplored secrets.

44
00:02:48,200 --> 00:02:50,800
He has already travelled
over five miles down

45
00:02:50,880 --> 00:02:52,920
to the very bottom of
the Atlantic Ocean.

46
00:02:53,000 --> 00:02:54,960
Oh, my goodness.
I can see the bottom.

47
00:02:57,880 --> 00:03:01,520
Now he and his team are heading
for a far tougher challenge.

48
00:03:05,120 --> 00:03:07,400
The Southern Ocean.

49
00:03:07,480 --> 00:03:10,520
It surrounds the frozen continent
of Antarctica.

50
00:03:12,000 --> 00:03:14,480
These are the coldest waters
on the planet

51
00:03:14,560 --> 00:03:16,520
and some of the roughest seas,

52
00:03:16,600 --> 00:03:20,680
making it perhaps the most dangerous
of all the Earth's oceans.

53
00:03:20,760 --> 00:03:24,320
Some of the old-style maps
had "here be dragons"

54
00:03:24,400 --> 00:03:27,080
and sailors were actually terrified
to come to this area

55
00:03:27,160 --> 00:03:29,760
because it was so dangerous.
And ships did not return.

56
00:03:29,840 --> 00:03:31,440
They would be destroyed.

57
00:03:37,920 --> 00:03:41,480
Rising winds are already testing
the crew and equipment.

58
00:03:43,320 --> 00:03:45,200
Getting a little brisk out here
already.

59
00:03:45,280 --> 00:03:47,880
It's lovely. Might have to
take the shorts off.

60
00:03:47,960 --> 00:03:51,080
Will have to go to
long pants soon.

61
00:03:51,160 --> 00:03:53,640
Boy, it came up, huh?

62
00:03:54,920 --> 00:03:56,760
Colin, you need more stuff?

63
00:04:02,440 --> 00:04:05,840
Soon, they're experiencing
a full-scale snow storm.

64
00:04:05,920 --> 00:04:07,800
me.

65
00:04:09,640 --> 00:04:12,040
It should be dead ahead somewhere.

66
00:04:12,120 --> 00:04:14,160
I'll just lower the starboard
a little bit.

67
00:04:16,200 --> 00:04:17,800
Yeah, I got it.

68
00:04:17,880 --> 00:04:20,080
In this life, I'd rather be lucky
than good.

69
00:04:20,160 --> 00:04:23,360
And when it comes to weather,
you definitely want to be lucky.

70
00:04:23,440 --> 00:04:26,680
Victor is worried about the effects
of the cold

71
00:04:26,760 --> 00:04:29,760
on the expedition's vital
navigation equipment.

72
00:04:29,840 --> 00:04:32,800
Batteries look OK.

73
00:04:32,880 --> 00:04:34,960
Modems.

74
00:04:35,040 --> 00:04:37,440
Yeah, these guys did well.

75
00:04:37,520 --> 00:04:40,320
Very strange seeing snow
on my landers.

76
00:04:42,240 --> 00:04:44,360
The snow storm has been
an early warning

77
00:04:44,440 --> 00:04:47,200
of the treacherous weather
that could lie ahead.

78
00:04:52,720 --> 00:04:54,760
To search for the ocean's
deepest point,

79
00:04:54,840 --> 00:04:58,720
Victor and his team are heading
for a dramatic underwater chasm

80
00:04:58,800 --> 00:05:01,400
called the South Sandwich Trench.

81
00:05:03,640 --> 00:05:05,840
Over four and a half miles deep,

82
00:05:05,920 --> 00:05:09,280
its waters drop below freezing

83
00:05:09,360 --> 00:05:11,760
and are under huge pressure.

84
00:05:11,840 --> 00:05:16,000
Five times the crushing power
of a junkyard car compactor.

85
00:05:16,080 --> 00:05:20,240
It's very rarely visited.
And certainly no-one has ever mapped

86
00:05:20,320 --> 00:05:22,240
the South Sandwich Trench.

87
00:05:22,320 --> 00:05:25,280
Certainly not with the kind of tools
we will have available.

88
00:05:25,360 --> 00:05:28,360
This is very exciting
for the whole crew

89
00:05:28,440 --> 00:05:30,600
because this is true exploration.

90
00:05:30,680 --> 00:05:32,680
To protect Victor from

91
00:05:32,760 --> 00:05:35,320
the deadly pressures at
the bottom of the trench,

92
00:05:35,400 --> 00:05:37,840
he has commissioned a remarkable
prototype sub

93
00:05:37,920 --> 00:05:40,480
at a cost of 35 million dollars.

94
00:05:40,560 --> 00:05:43,880
Surrounding the cockpit is
a sphere

95
00:05:43,960 --> 00:05:46,120
of 3.5-inch thick titanium

96
00:05:46,200 --> 00:05:50,160
punctured by wide-angled
view ports made of acrylic.

97
00:05:50,240 --> 00:05:53,280
It's equipped with
enough oxygen tanks

98
00:05:53,360 --> 00:05:55,680
to give him air for up to four days.

99
00:05:55,760 --> 00:05:59,520
But in the Southern Ocean,
the sub will have to endure

100
00:05:59,600 --> 00:06:03,200
temperatures far colder
than any it's experienced before.

101
00:06:03,280 --> 00:06:06,760
We'll have surface temperatures
that are starting at zero,

102
00:06:06,840 --> 00:06:09,720
or one degree, rather than
where we were before

103
00:06:09,800 --> 00:06:12,920
where the surface temperatures
were 25 or 30 degrees Celsius.

104
00:06:13,000 --> 00:06:15,760
At depth, it'll be minus one.

105
00:06:15,840 --> 00:06:19,960
It's enough to affect our cabling,
our connectors, our batteries.

106
00:06:20,040 --> 00:06:23,360
If the dive succeeds,
the expedition scientists

107
00:06:23,440 --> 00:06:26,360
will be able to hunt for
unknown creatures
of the deep...

108
00:06:26,440 --> 00:06:28,040
Prepare lights on sub.

109
00:06:29,080 --> 00:06:32,680
..and try to solve one of the
Southern Ocean's greatest
mysteries.

110
00:06:35,160 --> 00:06:38,600
These waters are, in fact,
packed with oxygen and nutrients

111
00:06:38,680 --> 00:06:40,760
vital to life

112
00:06:40,840 --> 00:06:43,520
and are the source of a global
ocean current

113
00:06:43,600 --> 00:06:45,200
that feeds the world.

114
00:06:46,280 --> 00:06:49,640
Scientists are desperate to find
where this lifeblood current

115
00:06:49,720 --> 00:06:51,720
exits the Southern Ocean.

116
00:06:51,800 --> 00:06:55,240
The South Sandwich Trench
is a prime suspect.

117
00:06:55,320 --> 00:06:58,960
But no-one has been able to dive
deep enough to confirm it.

118
00:06:59,040 --> 00:07:01,840
The Southern Ocean,
in my opinion,

119
00:07:01,920 --> 00:07:04,960
is one of the most important
locations of the planet.

120
00:07:05,040 --> 00:07:07,400
It's the lungs of Earth.

121
00:07:07,480 --> 00:07:10,160
It's vital to global
ocean circulation.

122
00:07:10,240 --> 00:07:13,160
So we need to know more.
We want to know more.

123
00:07:13,240 --> 00:07:16,560
To make their bold attempt,
Victor and his team

124
00:07:16,640 --> 00:07:18,640
only have a short window of time.

125
00:07:18,720 --> 00:07:20,720
The brief Antarctic summer,

126
00:07:20,800 --> 00:07:25,040
when the pack ice that locks in
over seven million square miles
of ocean,

127
00:07:25,120 --> 00:07:26,960
melts and retreats.

128
00:07:31,240 --> 00:07:34,160
You look at the Southern Ocean,
every winter we grow

129
00:07:34,240 --> 00:07:37,360
almost the equivalent of the
Continental United States.

130
00:07:37,440 --> 00:07:40,760
And in summer, melt that
entire continent back.

131
00:07:45,320 --> 00:07:48,880
To make their final preparations
before reaching the deep trench,

132
00:07:48,960 --> 00:07:52,480
the team are docking at
the remote island of South Georgia.

133
00:07:52,560 --> 00:07:54,880
Yeah, you wouldn't want to
anchor here.

134
00:07:54,960 --> 00:07:57,120
Maybe a little too much chain.

135
00:07:59,480 --> 00:08:02,840
It's home to hundreds of thousands
of king penguins.

136
00:08:04,600 --> 00:08:07,000
One of the largest penguin species
on Earth.

137
00:08:09,640 --> 00:08:11,240
There are fur seals.

138
00:08:15,440 --> 00:08:17,920
And enormous elephant seals

139
00:08:18,000 --> 00:08:21,720
that can weigh in at over
8,000 pounds.

140
00:08:23,640 --> 00:08:26,680
There are only a few days left
of the Antarctic summer

141
00:08:26,760 --> 00:08:30,640
and the window to find and dive
the deepest point
in the Southern Ocean

142
00:08:30,720 --> 00:08:33,720
is closing. But first,

143
00:08:33,800 --> 00:08:35,600
they must trial a new launch
method.

144
00:08:35,680 --> 00:08:39,360
During their first expedition
to the Atlantic deep,

145
00:08:39,440 --> 00:08:42,520
Victor boarded the sub
from an inflatable RIB.

146
00:08:42,600 --> 00:08:47,560
But catastrophe hit as rough seas
caused Victor to slip.

147
00:08:52,680 --> 00:08:54,960
In the tropical temperatures
around Puerto Rico,

148
00:08:55,040 --> 00:08:57,120
the risks were minimal.

149
00:08:59,960 --> 00:09:01,880
But here, in Antarctic waters,

150
00:09:01,960 --> 00:09:05,480
a similar accident would put
his life in serious danger.

151
00:09:07,080 --> 00:09:09,400
It's a really dangerous situation

152
00:09:09,480 --> 00:09:11,520
that I'm worried about.

153
00:09:11,600 --> 00:09:14,880
And we've got a whole
risk management plan

154
00:09:14,960 --> 00:09:17,080
to deal with that exact issue.

155
00:09:18,720 --> 00:09:21,440
The crew have worked out a way
to suspend the sub

156
00:09:21,520 --> 00:09:24,360
against a giant buffer
at the back of the ship,

157
00:09:24,440 --> 00:09:27,840
allowing Victor access via
a carbon fibre plank.

158
00:09:29,480 --> 00:09:33,240
But there's still a steep drop
between the ship and submarine.

159
00:09:33,320 --> 00:09:35,880
That's kind of the gap
we're worried about.

160
00:09:35,960 --> 00:09:39,640
If someone falls in that gap,
that would be not a good thing.

161
00:09:41,120 --> 00:09:43,440
You're gonna be moving around
a little bit more

162
00:09:43,520 --> 00:09:46,280
when we're in the rougher seas.
But it's still high enough

163
00:09:46,360 --> 00:09:50,480
that it'll stay with the ship.
It'll move with the ship
and the sub will move together.

164
00:09:50,560 --> 00:09:52,160
It's gonna be nice and stable.

165
00:09:55,760 --> 00:09:59,600
A little easier than clambering up
that .

166
00:09:59,680 --> 00:10:02,960
One, two... Beautiful.

167
00:10:11,320 --> 00:10:13,960
Great.

168
00:10:14,040 --> 00:10:16,680
I didn't sleep at all last night,
just thinking about

169
00:10:16,760 --> 00:10:19,400
that boarding system. But, er,

170
00:10:19,480 --> 00:10:21,080
it went really well.

171
00:10:22,080 --> 00:10:25,320
The team are finally ready
to embark on their first test dive

172
00:10:25,400 --> 00:10:27,120
in the Southern Ocean.

173
00:10:27,200 --> 00:10:29,640
I'm excited. I'm clear.

174
00:10:31,840 --> 00:10:34,920
But beyond the sheltered headlands
of South Georgia,

175
00:10:35,000 --> 00:10:37,280
it won't be easy.

176
00:10:37,360 --> 00:10:40,080
The Southern Ocean is by far
the most risky environment.

177
00:10:40,160 --> 00:10:42,760
You have these enormous
storm systems

178
00:10:42,840 --> 00:10:46,680
that create swell, and this swell
batters the side of a ship,

179
00:10:46,760 --> 00:10:48,760
batters the side of a submersible,

180
00:10:48,840 --> 00:10:51,920
then the submersible sinks
down into

181
00:10:52,000 --> 00:10:54,200
what could possibly be
a very strong ocean jet.

182
00:10:54,280 --> 00:10:57,280
We'd have to fight that jet down
to stay in one place

183
00:10:57,360 --> 00:11:00,720
all the way down until it gets
within the confines of the trench.

184
00:11:00,800 --> 00:11:03,040
And then it would be safe
and sheltered.

185
00:11:09,120 --> 00:11:11,600
100 miles away from
the deepest point,

186
00:11:11,680 --> 00:11:14,120
the team sees the chance
of a break in the weather

187
00:11:14,200 --> 00:11:17,160
to take the sub on an
exploratory dive.

188
00:11:17,240 --> 00:11:20,280
It's an opportunity for Chief
Scientist Alan Jamieson

189
00:11:20,360 --> 00:11:23,120
to search for new creatures
of the deep

190
00:11:23,200 --> 00:11:25,480
and for Victor to put the sub
through its paces

191
00:11:25,560 --> 00:11:27,680
in the Southern Ocean's
freezing waters.

192
00:11:30,360 --> 00:11:33,840
In the spotlight is
the sub's designer, John Ramsay.

193
00:11:33,920 --> 00:11:36,560
Mechanically, everything
is great at cold temperatures.

194
00:11:36,640 --> 00:11:38,560
It's the electrical issues

195
00:11:38,640 --> 00:11:41,520
with cold circuit boards
and things like that.

196
00:11:41,600 --> 00:11:44,080
Just hoping everything's
gonna be fine for the guys.

197
00:11:44,160 --> 00:11:47,840
First, the team needs to launch
their 35-million-dollar sub

198
00:11:47,920 --> 00:11:52,360
off the back of a ship being
buffeted by the volatile
Southern Ocean.

199
00:11:52,440 --> 00:11:55,440
The most dangerous part of
any of our operations

200
00:11:55,520 --> 00:11:57,480
will always be launch and recovery.

201
00:11:57,560 --> 00:12:02,200
That's when you're dealing with
forces that are unpredictable,

202
00:12:02,280 --> 00:12:04,120
and managing that
is a difficult thing.

203
00:12:04,200 --> 00:12:08,360
We're ready to launch here.
We're rolling, but we'll give it
a shot.

204
00:12:10,960 --> 00:12:13,040
Let's do this. Out on the A-frame.

205
00:12:13,120 --> 00:12:14,840
Following the tagline slowly.

206
00:12:18,240 --> 00:12:20,360
The waves are coming in
behind us.

207
00:12:20,440 --> 00:12:23,800
Be advised, it's gonna get
a little sloppy here for a minute.

208
00:12:23,880 --> 00:12:26,560
This is where we start
to rock 'n' roll.
Here we go, boys.

209
00:12:26,640 --> 00:12:29,360
You're gonna have to go quick.
This is the worst part.

210
00:12:29,440 --> 00:12:32,320
Back on the main! Back on the main!

211
00:12:32,400 --> 00:12:34,960
We're out of time.
Let go of the line a little bit!

212
00:12:43,880 --> 00:12:46,280
me.
Just hang on. Hang on, buddy.

213
00:12:49,320 --> 00:12:52,640
Get that out on the tow line!
Whoa, whoa, whoa, whoa!

214
00:12:54,600 --> 00:12:56,200
Why are we doing this?

215
00:13:01,000 --> 00:13:02,600
Out on the tow line.

216
00:13:02,680 --> 00:13:06,280
To have that happen right
at the moment you're
releasing it.

217
00:13:06,360 --> 00:13:08,600
You know, that's
a sickening feeling.

218
00:13:13,880 --> 00:13:16,040
Status, please?
Just be advised, uh,

219
00:13:16,120 --> 00:13:19,480
looks like you may have lost
some starboard panel.

220
00:13:19,560 --> 00:13:21,200
Roger that. Permission to dive.

221
00:13:21,280 --> 00:13:24,840
Negative, negative.
You won't be released until...

222
00:13:24,920 --> 00:13:26,960
Then let's pick up the, uh...
Yep.

223
00:13:36,160 --> 00:13:38,800
What happened to the tow line?
We broke the tow line.

224
00:13:38,880 --> 00:13:41,040
We'll get her, Ricky.

225
00:13:41,120 --> 00:13:43,680
Without its tow line,
the sub is now adrift.

226
00:13:43,760 --> 00:13:46,560
The team must clear
the remaining lines

227
00:13:46,640 --> 00:13:50,240
and avoid getting freezing
water inside their protective
clothing.

228
00:13:52,000 --> 00:13:53,960
In the cold water
of the Southern Ocean,

229
00:13:54,040 --> 00:13:56,920
if you go into the water,
you've only got about a minute

230
00:13:57,000 --> 00:13:59,120
before you're in serious trouble.

231
00:14:02,440 --> 00:14:04,600
Let's get ready in case
he falls in the water.

232
00:14:06,280 --> 00:14:07,880
What am I supposed to do?

233
00:14:15,720 --> 00:14:20,080
After rough seas caused
the sub to collide with
the back of the ship on launch,

234
00:14:20,160 --> 00:14:22,880
the sub has lost one of its
external cameras.

235
00:14:22,960 --> 00:14:26,080
The team can't see
any other damage

236
00:14:26,160 --> 00:14:28,560
and decide to press ahead
with the dive.

237
00:14:28,640 --> 00:14:31,520
LF, this is SO.
Yeah, go ahead.

238
00:14:31,600 --> 00:14:34,600
OK, you're clear to dive.
Clear to dive.

239
00:14:34,680 --> 00:14:36,600
Pumping in.
OK, here we go.

240
00:14:47,680 --> 00:14:50,600
We're descending.
We're underwater.

241
00:14:50,680 --> 00:14:52,520
It's eerily quiet.
Yeah.

242
00:14:56,520 --> 00:14:58,320
The green colour
of the water here

243
00:14:58,400 --> 00:15:01,040
is evidence of what makes
the Southern Ocean

244
00:15:01,120 --> 00:15:03,280
so vital to life
around the world.

245
00:15:03,360 --> 00:15:05,480
Plentiful nutrients
build up here

246
00:15:05,560 --> 00:15:07,280
during the long, dark winters,

247
00:15:07,360 --> 00:15:10,360
and in the summer feed
explosions of microscopic plants

248
00:15:10,440 --> 00:15:12,880
called phytoplankton.

249
00:15:12,960 --> 00:15:14,840
They bloom in such quantities

250
00:15:14,920 --> 00:15:18,480
that NASA has even been able
to track them from space.

251
00:15:18,560 --> 00:15:22,040
It was mind-blowing that on
that type of scale

252
00:15:22,120 --> 00:15:25,880
in the Southern Ocean,
the phytoplankton were responding
to the surface currents

253
00:15:25,960 --> 00:15:27,840
and the winds, and their
distribution,

254
00:15:27,920 --> 00:15:29,880
and you could see that
from space.

255
00:15:29,960 --> 00:15:32,120
Plants depend on light

256
00:15:32,200 --> 00:15:35,320
and so they live in a narrow band
near the surface,

257
00:15:35,400 --> 00:15:38,360
the Sunlight Zone.

258
00:15:38,440 --> 00:15:41,040
And here, they in turn
support an abundance

259
00:15:41,120 --> 00:15:43,320
of microorganisms
called krill

260
00:15:43,400 --> 00:15:47,160
which feed a rich food chain,
from penguins...

261
00:15:48,760 --> 00:15:50,360
..to killer whales.

262
00:15:54,200 --> 00:15:56,240
Passing below 650 feet,

263
00:15:56,320 --> 00:16:00,400
the sub enters the Twilight Zone.

264
00:16:00,480 --> 00:16:03,600
Here, the light dwindles and
the ocean's microscopic plants

265
00:16:03,680 --> 00:16:05,280
can no longer survive.

266
00:16:06,560 --> 00:16:09,000
Yet life does thrive here.

267
00:16:09,080 --> 00:16:12,600
Like this ice fish.
Its blood still runs

268
00:16:12,680 --> 00:16:16,120
because it has a natural
antifreeze in its veins.

269
00:16:19,400 --> 00:16:22,960
And transparent, jelly-like
organisms called salps

270
00:16:23,040 --> 00:16:25,360
that string together
in long chains.

271
00:16:28,400 --> 00:16:31,240
Look how dark it is.
That's incredible, isn't it?

272
00:16:31,320 --> 00:16:35,960
Surface, this is LF.
Present depth, 348 metres.

273
00:16:37,920 --> 00:16:41,120
Victor and Alan have been
underwater for just ten minutes,

274
00:16:41,200 --> 00:16:43,560
but the surface crew
have spotted evidence

275
00:16:43,640 --> 00:16:45,880
of a worrying fault
with the sub.

276
00:16:45,960 --> 00:16:48,760
I think it's best to report,
just in case. Yeah.

277
00:16:48,840 --> 00:16:51,360
Kelvin, Gino.
Go ahead.

278
00:16:51,440 --> 00:16:55,480
Looks like
I can see a small oil slick.

279
00:16:57,760 --> 00:17:01,240
It seems that when one of the sub's
cameras was damaged on launch,

280
00:17:01,320 --> 00:17:06,480
it breached the oil-filled pipes
that carry electrical wires
around the sub.

281
00:17:06,560 --> 00:17:09,960
It's now only a matter of time
before seawater gets in

282
00:17:10,040 --> 00:17:13,800
and shorts out a vital part
of the electrical system.

283
00:17:13,880 --> 00:17:16,400
The sub's power comes from
six batteries

284
00:17:16,480 --> 00:17:19,880
packed into detachable pods
on either side of the sphere.

285
00:17:19,960 --> 00:17:22,640
They, in turn,
link to junction boxes

286
00:17:22,720 --> 00:17:24,920
that supply the sub's components.

287
00:17:25,000 --> 00:17:28,720
To protect the wires
and electronics
from the pressures of the deep,

288
00:17:28,800 --> 00:17:31,440
the boxes and pipes
are all filled with oil.

289
00:17:31,520 --> 00:17:33,680
Because oil is lighter than water,

290
00:17:33,760 --> 00:17:37,000
it's now escaping from the breach
at the top of the sub,

291
00:17:37,080 --> 00:17:39,200
letting water seep in.

292
00:17:39,280 --> 00:17:41,280
If it reaches
the junction box,

293
00:17:41,360 --> 00:17:43,480
it will knock out
multiple components,

294
00:17:43,560 --> 00:17:46,520
leaving Victor without
full control of the sub

295
00:17:46,600 --> 00:17:49,480
2,000 feet below the surface.

296
00:17:49,560 --> 00:17:53,760
OK, response. Need you to
instruct the LF

297
00:17:53,840 --> 00:17:56,720
to abort the dive. They're
gonna have to abort the dive.

298
00:17:56,800 --> 00:17:59,120
There are times when you have to
call it,

299
00:17:59,200 --> 00:18:02,320
and even if it's unpopular,
you do it because

300
00:18:02,400 --> 00:18:04,320
you have to do what's safe.

301
00:18:04,400 --> 00:18:08,200
LF, this is the response.
Please abort the dive.

302
00:18:08,280 --> 00:18:09,880
Abort the dive.

303
00:18:11,680 --> 00:18:13,360
Roger that. Aborting dive.

304
00:18:13,440 --> 00:18:15,920
Repeat. Aborting dive.
Why?

305
00:18:16,000 --> 00:18:18,200
When we lost the camera,
it sheared the cable

306
00:18:18,280 --> 00:18:20,560
so oil started leaking.
Oh.

307
00:18:20,640 --> 00:18:23,240
Victor must now make
a controlled release

308
00:18:23,320 --> 00:18:27,720
of enough diving weights
to bring the sub safely
back to the surface.

309
00:18:27,800 --> 00:18:29,400
Ejecting weights.

310
00:18:30,400 --> 00:18:33,480
All weights jettisoned.
Ascending to surface.

311
00:18:33,560 --> 00:18:36,080
Get ready to brace.

312
00:18:50,800 --> 00:18:54,120
We had to abort you, man.
Cos you would have lost your...

313
00:18:54,200 --> 00:18:56,200
you'd have lost your modem
anyway. I know.

314
00:18:56,280 --> 00:18:59,240
At some point, you'd have come up
even if you didn't want to.

315
00:19:02,680 --> 00:19:05,440
Repairs to the damaged sub
begin.

316
00:19:05,520 --> 00:19:07,560
OK, try it a little bit.

317
00:19:07,640 --> 00:19:10,240
And the team encounter
another deadly hazard

318
00:19:10,320 --> 00:19:11,920
of the Southern Ocean.

319
00:19:13,560 --> 00:19:15,760
Icebergs.

320
00:19:15,840 --> 00:19:18,920
A specialist ice pilot has
joined forces with the captain

321
00:19:19,000 --> 00:19:22,280
to navigate through these
unpredictable ship sinkers.

322
00:19:22,360 --> 00:19:26,800
Nine tenths of an iceberg
is underneath the ice.

323
00:19:29,120 --> 00:19:32,160
And I've seen icebergs going
against the wind

324
00:19:32,240 --> 00:19:34,960
which is completely
not intuitive.

325
00:19:36,320 --> 00:19:39,960
To begin with, the icebergs
are relatively small.

326
00:19:40,040 --> 00:19:42,640
But then comes a monster.

327
00:19:44,920 --> 00:19:47,600
That's the target.
It's dead ahead of us now.

328
00:19:47,680 --> 00:19:51,080
Is this the biggest you've ever...
I've never seen one this big.

329
00:19:51,160 --> 00:19:54,720
It's extraordinary.
It goes off into the horizon.

330
00:19:54,800 --> 00:19:57,400
And it disappears
off into the fog.

331
00:19:57,480 --> 00:20:01,080
And then disappears off
into the fog on the other side.

332
00:20:01,160 --> 00:20:03,720
This is massive!
How long is it, Stu?

333
00:20:03,800 --> 00:20:07,240
18 miles, this one, I think.
More than a half marathon long.

334
00:20:08,800 --> 00:20:11,080
Icebergs actually pose
a true danger,

335
00:20:11,160 --> 00:20:13,120
so when I'm coming up
from the bottom

336
00:20:13,200 --> 00:20:15,920
I don't want to be going up
too fast because I don't know

337
00:20:16,000 --> 00:20:17,600
what's directly on top of me.

338
00:20:19,760 --> 00:20:23,280
Finally, the team arrive above
the South Sandwich Trench,

339
00:20:23,360 --> 00:20:25,440
a vast underwater canyon

340
00:20:25,520 --> 00:20:28,040
that's a staggering
4.5 miles deep.

341
00:20:28,120 --> 00:20:32,000
Their first task is to identify
on the floor of the trench

342
00:20:32,080 --> 00:20:35,880
the precise location of
the deepest point
in the Southern Ocean.

343
00:20:35,960 --> 00:20:40,520
Using one of the most powerful
sonar scanning systems
in the world,

344
00:20:40,600 --> 00:20:43,840
they begin to map,
for the very first time in history,

345
00:20:43,920 --> 00:20:46,440
an extraordinary
hidden landscape.

346
00:20:46,520 --> 00:20:49,520
If this were inverted
and was a mountain range,

347
00:20:49,600 --> 00:20:53,320
it would actually be higher
than the entire Andes mountain
chain.

348
00:20:53,400 --> 00:20:55,000
It's massive.

349
00:20:56,720 --> 00:21:00,760
The South Sandwich Trench
is a staggering 600 miles long,

350
00:21:00,840 --> 00:21:03,480
stretching from the lower reaches
of the Atlantic

351
00:21:03,560 --> 00:21:05,960
down into the Southern Ocean
itself.

352
00:21:08,160 --> 00:21:11,520
But up on the bridge,
the team spot a growing threat

353
00:21:11,600 --> 00:21:13,280
to the deep dive.

354
00:21:13,360 --> 00:21:15,840
The storms are moving faster
than expected.

355
00:21:15,920 --> 00:21:19,480
The two low-pressure systems
are causing all this weather
to go in a funnel.

356
00:21:19,560 --> 00:21:22,920
We can't outrun it.
We point the ship into the storm
and we ride it out.

357
00:21:25,720 --> 00:21:28,280
In the freezing waters
of the Southern Ocean,

358
00:21:28,360 --> 00:21:30,720
an approaching storm
is threatening to derail

359
00:21:30,800 --> 00:21:34,200
Victor's attempt to discover
and dive its deepest point.

360
00:21:34,280 --> 00:21:36,080
We are in the screaming 60s.

361
00:21:36,160 --> 00:21:38,400
You do not hang out
at this latitude

362
00:21:38,480 --> 00:21:40,840
and not have storms
come at you.

363
00:21:40,920 --> 00:21:43,640
Even if it's rough weather,
we're gonna tough it out.

364
00:21:43,720 --> 00:21:48,200
Yes, sir.
Even if we don't dive,
we'll deploy the landers.

365
00:21:48,280 --> 00:21:50,680
The landers are underwater
scientific probes

366
00:21:50,760 --> 00:21:54,320
packed with sensors,
cameras and traps.

367
00:21:54,400 --> 00:21:58,320
They are vital for the team's
mission to explore what life

368
00:21:58,400 --> 00:22:03,440
could possibly exist in
the icy waters 24,000 feet below.

369
00:22:03,520 --> 00:22:06,680
Pretty exciting. We're at
the limits of this planet.

370
00:22:06,760 --> 00:22:10,280
Ultra-cold and high pressure
is very hard to adapt to.

371
00:22:10,360 --> 00:22:13,040
There are five landers
on board,

372
00:22:13,120 --> 00:22:15,600
costing up to $200,000 each.

373
00:22:15,680 --> 00:22:18,880
But with the storm on its way,
to launch and retrieve

374
00:22:18,960 --> 00:22:21,840
these near one-ton monsters
could put lives on the line.

375
00:22:21,920 --> 00:22:26,000
Hope it doesn't storm more.
We don't want ice forming
on the deck.

376
00:22:26,080 --> 00:22:27,760
If any one of us
fell in the water,

377
00:22:27,840 --> 00:22:31,040
cos it's so cold down here,
you get hypothermia
pretty fast.

378
00:22:31,120 --> 00:22:32,880
Hold on tight.

379
00:22:35,040 --> 00:22:37,920
Grab the wire.
It's going that way.

380
00:22:38,000 --> 00:22:40,480
Lines off!

381
00:22:40,560 --> 00:22:42,600
It's down.

382
00:22:44,320 --> 00:22:47,640
Despite the conditions,
two science probes

383
00:22:47,720 --> 00:22:49,480
are heading for the seabed.

384
00:22:51,320 --> 00:22:54,040
Eight hours later,
and after a remote release,

385
00:22:54,120 --> 00:22:56,440
they are due back
on the surface.

386
00:22:56,520 --> 00:22:59,920
But now the weather is taking
a dramatic turn for the worse.

387
00:23:00,000 --> 00:23:03,920
The nature of what we do
is notoriously dangerous

388
00:23:04,000 --> 00:23:06,880
in terms of equipment wise
and weather wise.

389
00:23:06,960 --> 00:23:11,480
You psychologically prepare yourself
because you can plan an expedition
for two years

390
00:23:11,560 --> 00:23:13,720
and you go there
and it just goes wrong.

391
00:23:13,800 --> 00:23:16,480
Where are they?

392
00:23:17,680 --> 00:23:19,960
We have the visuals.

393
00:23:20,040 --> 00:23:23,880
About 800 metres away.

394
00:23:28,400 --> 00:23:30,000
Oh, man.

395
00:23:34,520 --> 00:23:37,600
Just watch that.
It just takes one little roll.

396
00:23:42,400 --> 00:23:45,520
Getting scary.
Come down.

397
00:23:48,840 --> 00:23:50,640
Coming up!

398
00:23:52,240 --> 00:23:54,480
I'm sending the wire.

399
00:23:57,880 --> 00:24:00,080
Where is it?

400
00:24:00,160 --> 00:24:02,680
It hasn't worked.

401
00:24:03,680 --> 00:24:06,080
All right?
No.

402
00:24:09,040 --> 00:24:11,840
See what happened to the rope?
Yeah.

403
00:24:11,920 --> 00:24:14,080
Looks like something chewed it,
doesn't it?

404
00:24:16,880 --> 00:24:19,440
A crucial piece of
scientific equipment

405
00:24:19,520 --> 00:24:22,120
and any extreme lifeforms
it may have captured

406
00:24:22,200 --> 00:24:24,520
are now plummeting
back to the seabed,

407
00:24:24,600 --> 00:24:26,200
never to be seen again.

408
00:24:28,480 --> 00:24:30,600
And now comes more bad news.

409
00:24:30,680 --> 00:24:32,640
The crew have failed
to locate

410
00:24:32,720 --> 00:24:34,960
the second probe.

411
00:24:35,040 --> 00:24:37,640
We should be seeing that probe
clear as daylight there.

412
00:24:37,720 --> 00:24:41,480
And because the Antarctic
winter is now fast approaching,

413
00:24:41,560 --> 00:24:44,880
they must abandon the search
and move on.

414
00:24:46,680 --> 00:24:49,720
Very distressing.
We have limited time

415
00:24:49,800 --> 00:24:52,600
and with bad weather
coming we might not get
another chance.

416
00:24:57,960 --> 00:25:01,680
There is better news
for the sonar team
mapping the trench.

417
00:25:01,760 --> 00:25:03,600
Wow. Where's that?

418
00:25:03,680 --> 00:25:06,000
This is a sea mound
that's 1100 metres

419
00:25:06,080 --> 00:25:07,680
off the sea floor.

420
00:25:09,200 --> 00:25:12,400
The sea mound is an extinct
underwater volcano.

421
00:25:12,480 --> 00:25:16,280
Previously unknown,
the team get to name it.

422
00:25:16,360 --> 00:25:19,760
It's a stark reminder that
we know more about
the surface of the moon

423
00:25:19,840 --> 00:25:22,000
than the seabed
of our own planet.

424
00:25:22,080 --> 00:25:23,680
It's just fantastic.

425
00:25:23,760 --> 00:25:26,120
Nobody knew anything about
this area.

426
00:25:26,200 --> 00:25:30,120
And look at all the amazing
features that have been imaged
by the sonar.

427
00:25:30,200 --> 00:25:33,920
The new data also bolsters
the theory

428
00:25:34,000 --> 00:25:36,760
that the South Sandwich Trench
is the root of

429
00:25:36,840 --> 00:25:39,560
the mysterious lifeblood current
which feeds the world.

430
00:25:39,640 --> 00:25:42,880
When you carve trenches
in the ocean,

431
00:25:42,960 --> 00:25:46,240
you create a funnel
where water flows.

432
00:25:46,320 --> 00:25:49,960
Are these trenches
reservoirs relatively undisturbed?

433
00:25:50,040 --> 00:25:53,240
Or are they dynamic
through-flows of water?

434
00:25:53,320 --> 00:25:55,640
To confirm the theory,

435
00:25:55,720 --> 00:25:58,520
the team need to sample
the deep trench itself.

436
00:25:58,600 --> 00:26:00,800
And now,
for the first time in history,

437
00:26:00,880 --> 00:26:04,240
they've accurately pinpointed
the very deepest site

438
00:26:04,320 --> 00:26:06,160
in the Southern Ocean.

439
00:26:06,240 --> 00:26:09,160
Based on the satellite data,
this one has always been the one

440
00:26:09,240 --> 00:26:11,800
that we thought was going to be
the deepest,

441
00:26:11,880 --> 00:26:16,400
or this last one.
No-one considered a third one.

442
00:26:16,480 --> 00:26:20,200
Now we know the deepest point
in the Southern Ocean

443
00:26:20,280 --> 00:26:22,400
is the yellow dot right here.
Wow.

444
00:26:24,720 --> 00:26:28,920
A staggering 24,388 feet
below the surface.

445
00:26:29,000 --> 00:26:32,160
this is Victor's target
for a dive

446
00:26:32,240 --> 00:26:34,600
he's determined to take on
alone.

447
00:26:34,680 --> 00:26:37,720
Doing things solo,
you're completely responsible

448
00:26:37,800 --> 00:26:40,720
for everything that happens.
And you're doing it by yourself

449
00:26:40,800 --> 00:26:43,800
with such intense focus.
It makes it more interesting.

450
00:26:43,880 --> 00:26:46,680
It's more exciting.
You're completely on your own.

451
00:26:48,480 --> 00:26:52,000
There are now just days left
before the Antarctic summer ends

452
00:26:52,080 --> 00:26:54,320
and the Southern Ocean
becomes too dangerous

453
00:26:54,400 --> 00:26:58,400
to dive. With rough seas
forecast for tomorrow,

454
00:26:58,480 --> 00:27:00,520
it's now or never.

455
00:27:00,600 --> 00:27:04,080
But there are major concerns
for Victor's safety.

456
00:27:07,680 --> 00:27:10,000
I don't wanna slam into
the bottom of an iceberg.

457
00:27:10,080 --> 00:27:14,400
There are huge bricks
of ice out there. Apartment-sized
blocks of ice.

458
00:27:20,760 --> 00:27:23,960
Despite the risks,
they decide to press ahead.

459
00:27:24,040 --> 00:27:27,360
He's gonna make a very careful
and deliberate return
to the surface.

460
00:27:27,440 --> 00:27:30,240
We want to make sure that he
verifies himself

461
00:27:30,320 --> 00:27:32,440
with cameras
that the surface is clear.

462
00:27:32,520 --> 00:27:36,120
Just in case we have him
misplaced on our chart.

463
00:27:36,200 --> 00:27:39,080
I'm gonna use light power
to slowly go up.

464
00:27:39,160 --> 00:27:41,520
I'm not gonna rock it up.

465
00:27:41,600 --> 00:27:43,880
The team prepare
to launch Victor

466
00:27:43,960 --> 00:27:46,920
on his historic attempt
into the freezing temperatures

467
00:27:47,000 --> 00:27:49,880
of the deep trench
beyond any hope of rescue.

468
00:27:49,960 --> 00:27:52,680
OK. You're gonna have a great dive.
It'll be awesome.

469
00:27:52,760 --> 00:27:55,080
Going to the bottom of the ocean
in a submersible

470
00:27:55,160 --> 00:27:58,680
is like going on a space mission
in terms of the isolation.

471
00:27:58,760 --> 00:28:00,760
Hatch coming down!
Hatch coming down.

472
00:28:00,840 --> 00:28:03,480
Thank you.
OK, let's do this.
Get him in, boys.

473
00:28:03,560 --> 00:28:08,520
The cold, extreme remoteness
will play on Victor's mind

474
00:28:08,600 --> 00:28:12,280
because if anything goes wrong,
you're right at the end

475
00:28:12,360 --> 00:28:14,920
of the most stretched
rubber band in history.

476
00:28:15,000 --> 00:28:17,920
And you're really hoping that
we'll pull you back.

477
00:28:20,440 --> 00:28:24,040
It's pumping in.
Proceeding to dive.

478
00:28:28,680 --> 00:28:31,720
Roger that, I'll try and
cross this down. Thanks.

479
00:28:35,400 --> 00:28:37,000
And down we go!

480
00:28:47,080 --> 00:28:50,040
Looking outside the portal,
looks like a lot of food down here.

481
00:28:50,120 --> 00:28:52,760
Oh, I just saw a jellyfish.

482
00:28:52,840 --> 00:28:56,800
Surface, LF. Present depth.

483
00:28:56,880 --> 00:28:59,760
Present depth, 487.

484
00:28:59,840 --> 00:29:02,760
Light support good.
Roger that, LF.

485
00:29:02,840 --> 00:29:05,680
We have you loud and clear.
Well, that was quick.

486
00:29:05,760 --> 00:29:07,680
Whoo!

487
00:29:07,760 --> 00:29:09,840
I mean he is whistling down!

488
00:29:09,920 --> 00:29:12,200
Within just minutes,

489
00:29:12,280 --> 00:29:15,280
Victor reaches the very deepest
zones of the Southern Ocean.

490
00:29:15,360 --> 00:29:17,280
The Midnight Zone.

491
00:29:17,360 --> 00:29:19,360
Where no light at all
can penetrate.

492
00:29:19,440 --> 00:29:22,680
And where extraordinary creatures
are still being discovered.

493
00:29:22,760 --> 00:29:26,360
The giant sea spider
whose internal organs

494
00:29:26,440 --> 00:29:29,080
are carried inside its legs.

495
00:29:31,320 --> 00:29:34,160
The feather star,
which uses the long spines

496
00:29:34,240 --> 00:29:37,440
along its arms to filter out
microscopic food

497
00:29:37,520 --> 00:29:39,360
from the water.

498
00:29:39,440 --> 00:29:42,920
And visitors from above.
Deep-diving sperm whales

499
00:29:43,000 --> 00:29:47,240
which have the largest brains
of any creature that's ever lived
on Earth.

500
00:29:50,520 --> 00:29:52,360
At 13,000 feet,

501
00:29:52,440 --> 00:29:54,920
Victor enters the Abyssal Zone.

502
00:29:55,000 --> 00:29:58,880
Home to sea pigs that inflate
up to seven pairs of legs

503
00:29:58,960 --> 00:30:01,440
to walk around the sea floor.

504
00:30:03,400 --> 00:30:06,560
And alarm jellyfish
that if attacked

505
00:30:06,640 --> 00:30:08,320
emit bioluminescent flashes

506
00:30:08,400 --> 00:30:10,280
thought to act like
a burglar alarm

507
00:30:10,360 --> 00:30:12,960
to attract bigger predators
to the scene.

508
00:30:13,040 --> 00:30:17,480
Can already feel the cold
coming through the bottom
of the submersible.

509
00:30:17,560 --> 00:30:19,600
The temperature of
the saltwater outside

510
00:30:19,680 --> 00:30:22,400
has now dipped below freezing.

511
00:30:32,840 --> 00:30:35,920
I'm checking to see if I hear
something unusual.

512
00:30:36,000 --> 00:30:39,000
I don't have any systems on.
I'm not using thrusters.

513
00:30:39,080 --> 00:30:40,680
It's almost like a hum.

514
00:30:41,880 --> 00:30:44,440
It does sound like a low hum

515
00:30:44,520 --> 00:30:48,440
coming from outside the sub.
I haven't heard that before.

516
00:30:48,520 --> 00:30:52,400
There's so much background
noise right now.

517
00:30:52,480 --> 00:30:55,880
Seems to be coming from the
submarine,
you can't hear the surface.

518
00:30:55,960 --> 00:30:59,920
Surface, LF.
Present depth five-zero-three-one.

519
00:31:00,000 --> 00:31:05,160
I cannot read you.
LF,

520
00:31:05,240 --> 00:31:08,480
comms check. Comms check.

521
00:31:11,880 --> 00:31:15,040
He didn't hear me.
He didn't acknowledge.

522
00:31:17,760 --> 00:31:19,640
What's going on
with that thing?

523
00:31:19,720 --> 00:31:22,400
Do you read me?
Do you read me at all?

524
00:31:24,680 --> 00:31:29,240
As a submarine pilot,
you don't want to lose
communication with the surface.

525
00:31:29,320 --> 00:31:32,200
That's extremely dangerous.
Extremely dangerous.

526
00:31:35,560 --> 00:31:38,920
Status! Status!

527
00:31:39,000 --> 00:31:41,880
What the 's going on
where he can't hear us?

528
00:31:52,840 --> 00:31:56,040
Surface, surface.
How do you read?

529
00:31:56,120 --> 00:31:59,200
Loud and clear.
Loud and clear.

530
00:32:01,560 --> 00:32:06,440
Crystal clear audio.
I can hear him.

531
00:32:06,520 --> 00:32:09,480
It's a critical moment
in the dive.

532
00:32:09,560 --> 00:32:12,960
Should Victor abandon
or continue into the deep?

533
00:32:13,040 --> 00:32:16,200
Maybe it's some
cold water or something.

534
00:32:16,280 --> 00:32:20,680
3,00 metres from the bottom.
I may just keep going.

535
00:32:20,760 --> 00:32:26,040
I've come all this way.
We're gonna achieve
the mission here.

536
00:32:26,120 --> 00:32:28,800
I'm not gonna abort for comms out.

537
00:32:31,080 --> 00:32:34,240
As he descends further
into the trench,

538
00:32:34,320 --> 00:32:39,200
it's not just the communications
system under attack from
the freezing Antarctic waters.

539
00:32:44,360 --> 00:32:47,160
The electrical supply
to the external cameras

540
00:32:47,240 --> 00:32:49,000
has also cut out.

541
00:32:49,080 --> 00:32:51,720
Well, now I'm really alone.

542
00:32:51,800 --> 00:32:53,840
I don't have comms
to the surface,

543
00:32:53,920 --> 00:32:56,080
I'm in a submersible
by myself,

544
00:32:56,160 --> 00:32:58,760
going down to the bottom
of the Southern Ocean.

545
00:33:06,000 --> 00:33:09,520
In Mission Control,
it's been two hours

546
00:33:09,600 --> 00:33:12,160
since they last made contact
with the sub.

547
00:33:15,840 --> 00:33:18,040
Attention all stations.
Be advised

548
00:33:18,120 --> 00:33:22,480
that we can hear Victor but
we cannot communicate with him.

549
00:33:22,560 --> 00:33:25,640
He cannot hear us.
He's very close to the lander.

550
00:33:25,720 --> 00:33:28,880
Couple of hundred metres,
so he must be near the bottom.

551
00:33:30,880 --> 00:33:35,600
Insulation fault. That's probably
just some water residue.
Everything's looking good.

552
00:33:35,680 --> 00:33:38,480
I should be getting
really close now.

553
00:33:38,560 --> 00:33:40,840
Oh, my.

554
00:33:40,920 --> 00:33:43,560
I can see something
on the bottom.

555
00:33:43,640 --> 00:33:45,880
I'm seeing the bottom
much more clearly.

556
00:33:55,320 --> 00:33:57,960
I've just reached the bottom
of the Southern Ocean.

557
00:33:58,040 --> 00:34:01,160
Looks like a moonscape
out of one of my portholes.

558
00:34:01,240 --> 00:34:04,880
Surface, LF. At bottom.
Repeat. At bottom.

559
00:34:04,960 --> 00:34:07,280
On the bottom.

560
00:34:12,240 --> 00:34:14,920
I am at bottom.

561
00:34:15,000 --> 00:34:18,000
I'm at the bottom
of the Southern Ocean.

562
00:34:18,080 --> 00:34:22,040
Victor is an amazing
24,388 feet

563
00:34:22,120 --> 00:34:23,960
below the surface.

564
00:34:24,040 --> 00:34:26,920
Where no human
has ever been before.

565
00:34:31,400 --> 00:34:33,560
The team have also deployed
here

566
00:34:33,640 --> 00:34:35,400
their three remaining
science probes,

567
00:34:35,480 --> 00:34:38,640
or landers, baited
with tempting fish carcasses.

568
00:34:38,720 --> 00:34:41,960
And although Victor's
external sub cameras

569
00:34:42,040 --> 00:34:44,240
may have cut out, amazingly

570
00:34:44,320 --> 00:34:47,040
the cameras on the landers
are still working.

571
00:34:47,120 --> 00:34:50,960
They now capture Victor's
arrival at the bottom.

572
00:34:51,040 --> 00:34:54,760
His lights just visible
across the sea floor.

573
00:34:56,640 --> 00:34:58,720
These are the first ever
images

574
00:34:58,800 --> 00:35:01,760
captured at the bottom of
the South Sandwich Trench.

575
00:35:01,840 --> 00:35:04,240
And attracted by
the lander's bait,

576
00:35:04,320 --> 00:35:07,440
there's already a crowd of
super-strange specialists

577
00:35:07,520 --> 00:35:11,640
able to endure intense cold
and enormous pressure.

578
00:35:11,720 --> 00:35:15,240
See tiny white...
they're like perfectly white.

579
00:35:15,320 --> 00:35:16,920
They look like tadpoles.

580
00:35:18,160 --> 00:35:21,200
What's that over there?
A larger creature.

581
00:35:21,280 --> 00:35:25,360
Pink on the top.
It has a little pink head.

582
00:35:25,440 --> 00:35:28,080
Two big eyes.

583
00:35:28,160 --> 00:35:31,320
Oh, he's definitely swimming.
Swimming away from my blast.

584
00:35:31,400 --> 00:35:35,920
It seems that Victor
has identified a mysid,

585
00:35:36,000 --> 00:35:38,120
a type of crustacean
whose bright red colour

586
00:35:38,200 --> 00:35:42,320
in fact makes it even more invisible
in the pitch dark
of the deep ocean.

587
00:35:43,920 --> 00:35:46,440
1500 feet further up
the trench slope,

588
00:35:46,520 --> 00:35:49,320
a second lander is capturing
remarkable images

589
00:35:49,400 --> 00:35:52,160
of the range of life
that thrives here.

590
00:35:52,240 --> 00:35:56,560
Sea lilies, and tall,
tubular glass sponges.

591
00:35:56,640 --> 00:35:59,760
Both snag passing
microorganisms

592
00:35:59,840 --> 00:36:02,640
drifting past in the current.

593
00:36:02,720 --> 00:36:04,400
And higher up the slope still,

594
00:36:04,480 --> 00:36:07,320
a third lander is capturing
the first ever footage

595
00:36:07,400 --> 00:36:11,560
in this trench of a truly
remarkable creature.

596
00:36:11,640 --> 00:36:13,440
Known as a snail fish,

597
00:36:13,520 --> 00:36:17,800
this is the deepest-living
kind of fish yet discovered.

598
00:36:21,600 --> 00:36:25,680
And here are two new species
filmed for the very first time.

599
00:36:27,600 --> 00:36:29,920
The snail fish are not here
for the bait itself,

600
00:36:30,000 --> 00:36:33,280
but to pick off any scavengers
the bait attracts.

601
00:36:33,360 --> 00:36:36,400
Finally, the landers'
auto-release mechanisms

602
00:36:36,480 --> 00:36:39,120
activate, and they head
back to the surface.

603
00:36:43,960 --> 00:36:47,280
But now comes the massive challenge
of safely retrieving

604
00:36:47,360 --> 00:36:51,520
these 200,000-dollar
pieces of equipment
in heavy seas.

605
00:36:51,600 --> 00:36:55,040
What do we got?
I'll just be happy
if it lands on deck.

606
00:36:55,120 --> 00:36:58,400
Oh, .
The most difficult side
to catch it on.

607
00:36:58,480 --> 00:37:00,640
Having lost two landers
already,

608
00:37:00,720 --> 00:37:02,920
the pressure is on.

609
00:37:03,000 --> 00:37:06,280
We're gonna have to cross
the tag lines. Yeah.

610
00:37:06,360 --> 00:37:09,920
Oh. Don't lose your balance.
This thing is a nightmare.

611
00:37:10,000 --> 00:37:13,080
Whoa. Wait. Wait.
Wait, wait, wait.

612
00:37:15,840 --> 00:37:18,320
All right, got it.
Good.

613
00:37:19,960 --> 00:37:22,160
Right, what does the bait
look like?

614
00:37:26,200 --> 00:37:28,400
Oh, here we go.

615
00:37:28,480 --> 00:37:30,600
It's absolutely freezing.

616
00:37:30,680 --> 00:37:34,600
The team have a vital hoard
of specimens

617
00:37:34,680 --> 00:37:37,040
from 24,000 feet down

618
00:37:37,120 --> 00:37:39,200
whose chemical secrets
could set the stage

619
00:37:39,280 --> 00:37:41,800
for scientific breakthroughs
in the future.

620
00:37:41,880 --> 00:37:44,160
Hopefully, we'll discover
a few molecules

621
00:37:44,240 --> 00:37:49,080
that have to do with combination
of pressure and ultra-cold
temperatures.

622
00:37:49,160 --> 00:37:51,720
Those may have all kinds of
applications.

623
00:37:51,800 --> 00:37:56,640
In China, they've been able
to use the osmolyte that we
discovered in deep-sea animals

624
00:37:56,720 --> 00:38:01,280
to actually cure glaucoma,
which is a high-pressure disease
of the human eye.

625
00:38:03,000 --> 00:38:06,200
Sensors on the landers have
also brought back
vital information

626
00:38:06,280 --> 00:38:08,720
that could confirm the root
of the lifeblood current

627
00:38:08,800 --> 00:38:11,120
carrying nutrients
from the Southern Ocean

628
00:38:11,200 --> 00:38:12,960
to the rest of the world.

629
00:38:13,040 --> 00:38:16,000
The data is despatched
to the British Antarctic Survey

630
00:38:16,080 --> 00:38:20,200
in the UK, where a team
have been tracking the current
at shallower depths.

631
00:38:20,280 --> 00:38:22,480
The data we were very kindly given

632
00:38:22,560 --> 00:38:24,800
confirm that this is
Antarctic bottom water

633
00:38:24,880 --> 00:38:27,280
and it is going through
this trench.

634
00:38:27,360 --> 00:38:30,920
The actual flow through it
is tens of times the flow

635
00:38:31,000 --> 00:38:33,200
of the Amazon. Millions
of tons a second.

636
00:38:33,280 --> 00:38:37,040
It's a breakthrough that'll be vital
for future scientific work.

637
00:38:37,120 --> 00:38:39,280
We can measure the waters
flowing through

638
00:38:39,360 --> 00:38:43,240
to see any change,
any signals that are happening
before it spreads out

639
00:38:43,320 --> 00:38:45,400
across the whole of the world's
ocean floor.

640
00:38:45,480 --> 00:38:49,360
These very deep data
are gonna be very valuable
for a long time.

641
00:38:49,440 --> 00:38:51,480
I think that's a wrap.

642
00:38:51,560 --> 00:38:55,000
Surfacing line release.

643
00:38:55,080 --> 00:38:56,680
And we're heading up.

644
00:39:04,440 --> 00:39:06,920
Two and a half hours after
leaving the bottom,

645
00:39:07,000 --> 00:39:09,840
Victor is now approaching
the surface.

646
00:39:09,920 --> 00:39:12,640
But after his radio and cameras
cut out in the cold,

647
00:39:12,720 --> 00:39:16,480
he has no way of knowing
if there's an iceberg
in his path.

648
00:39:16,560 --> 00:39:19,480
If there is,
the sub could be pinned

649
00:39:19,560 --> 00:39:22,000
beneath the ice
with no way out.

650
00:39:30,400 --> 00:39:34,400
Come up slow. Hope I don't
hit an iceberg.

651
00:39:34,480 --> 00:39:36,720
I hear a thump,
I'm stopping quick.

652
00:39:36,800 --> 00:39:39,480
Going up.
Just be patient, Victor.

653
00:39:39,560 --> 00:39:41,920
100 metres to go.

654
00:39:43,440 --> 00:39:46,320
LF, comms check.
I hear you.

655
00:39:46,400 --> 00:39:48,160
Have visual?

656
00:40:08,480 --> 00:40:10,600
On surface. Repeat.
On surface.

657
00:40:10,680 --> 00:40:13,880
Yeah, we can see you.
I see him now.

658
00:40:23,640 --> 00:40:25,840
Welcome back, Victor.
Thank you, gentlemen.

659
00:40:25,920 --> 00:40:29,240
It's good to be back.
Gino is inbound, should be
there in any minute.

660
00:40:29,320 --> 00:40:31,720
Roger that. Gino inbound.

661
00:40:31,800 --> 00:40:35,120
We had some comm issues,
but we'll talk about that after.

662
00:40:35,200 --> 00:40:37,360
Just glad to have you back
on the surface

663
00:40:37,440 --> 00:40:40,800
and just rigging for recovery.
Roger that.

664
00:40:40,880 --> 00:40:44,320
Comms were a problem,
but the mission was a success.

665
00:40:44,400 --> 00:40:46,480
Indeed it was.
Indeed it was, sir.

666
00:40:46,560 --> 00:40:48,720
Great job.
Thank you, sir.

667
00:40:48,800 --> 00:40:50,640
Nice and slow. Nice and slow.

668
00:40:50,720 --> 00:40:54,320
The sub may be safely back
on the surface,

669
00:40:54,400 --> 00:40:56,680
but there's a final challenge
to overcome

670
00:40:56,760 --> 00:40:59,560
in the volatile waters
of the Southern Ocean.

671
00:41:03,080 --> 00:41:05,920
Oh, that was a big wave, guys.
The LF does not

672
00:41:06,000 --> 00:41:07,840
like being on the surface.

673
00:41:07,920 --> 00:41:09,600
It's designed to just dive.

674
00:41:09,680 --> 00:41:11,800
Get to the bottom,
get there quickly.

675
00:41:11,880 --> 00:41:14,880
And she's like a wild horse
when you try to put a rope on it

676
00:41:14,960 --> 00:41:16,600
and it just fights you, right?

677
00:41:21,160 --> 00:41:22,760
Up on the main.

678
00:41:26,280 --> 00:41:28,320
Get it, Steve.
Down on the main.

679
00:41:31,000 --> 00:41:32,600
Come on, Steve.
Go, go, go.

680
00:41:32,680 --> 00:41:34,840
Go!
All right, Steve.

681
00:41:34,920 --> 00:41:37,280
Two hands, man.
Up on the main. Up on the main.

682
00:41:39,960 --> 00:41:41,920
That's it. That's it, Patrick.

683
00:41:53,720 --> 00:41:56,360
Good job, buddy. Yup.

684
00:41:56,440 --> 00:41:59,120
How you doing, Steve?
You wanna get off there?

685
00:41:59,200 --> 00:42:00,840
I can jump in there
and do this.

686
00:42:00,920 --> 00:42:03,920
Steve, let's get you off.
No, it's too cold.

687
00:42:14,600 --> 00:42:16,200
Hang in there, buddy.

688
00:42:18,120 --> 00:42:20,440
Steve, let's get you off.

689
00:42:20,520 --> 00:42:23,200
To prevent the onset
of hypothermia,

690
00:42:23,280 --> 00:42:27,200
the expedition doctor must
bring Steve's body temperature
back up.

691
00:42:27,280 --> 00:42:29,920
He's sat him down next to
the heating duct

692
00:42:30,000 --> 00:42:31,640
in the sub's hangar.

693
00:42:31,720 --> 00:42:35,640
Finally, Steve's warm enough
to be moved inside.

694
00:42:39,440 --> 00:42:42,160
Yeah, the crew did right.

695
00:42:42,240 --> 00:42:46,080
Keep using your hands.
Good work. Thank you.

696
00:42:46,160 --> 00:42:49,520
Having lived on the Tropic of
Capricorn my whole life,

697
00:42:49,600 --> 00:42:51,440
that's close to the Equator,

698
00:42:51,520 --> 00:42:53,880
I don't do cold water.

699
00:43:05,120 --> 00:43:08,440
Welcome back, Victor.
Thank you. Good to be back.

700
00:43:08,520 --> 00:43:12,560
Good job, team!

701
00:43:12,640 --> 00:43:17,080
At last, Victor is
safely back on board.

702
00:43:17,160 --> 00:43:20,320
He's now the only person
to have reached

703
00:43:20,400 --> 00:43:22,840
the deepest point of the
Southern Ocean.

704
00:43:22,920 --> 00:43:25,200
The second of his five deeps.

705
00:43:26,960 --> 00:43:29,520
Good to be back.
Good to have you back.

706
00:43:31,560 --> 00:43:33,960
Some interesting moments,
feeling quite alone

707
00:43:34,040 --> 00:43:37,920
in the middle of the Southern Ocean,
but we got it done
and it's good to be back.

708
00:43:38,000 --> 00:43:40,880
All right. It's kinda cold.

709
00:43:43,120 --> 00:43:45,920
Ha-ha!
Thanks for getting me back.

710
00:43:47,760 --> 00:43:51,400
It's a very high-tech machine
that we took to a very inhospitable
place.

711
00:43:51,480 --> 00:43:54,280
And it was extraordinary.

712
00:43:54,360 --> 00:43:56,560
We're doing it
because we're explorers.

713
00:43:56,640 --> 00:43:58,720
Because we want to see.

714
00:43:58,800 --> 00:44:01,760
We want to push the boundaries.
We want to learn things

715
00:44:01,840 --> 00:44:03,520
that haven't been learned before.

716
00:44:03,600 --> 00:44:06,040
And we want to do it together
and bring it back

717
00:44:06,120 --> 00:44:08,120
and share with other people.