0:00:18 > 0:00:21My search for superhumans has brought me here, to Hollywood.
0:00:21 > 0:00:22But where I'm going is a world away
0:00:22 > 0:00:24from the bright lights of the movies,
0:00:24 > 0:00:27cos I'm going into the darkness.
0:00:29 > 0:00:31It's really dark down here and really creepy.
0:00:31 > 0:00:33And if I didn't have my torch I'd probably
0:00:33 > 0:00:35bang my head on one of these jagged rocks.
0:00:35 > 0:00:39To see down here without any light at all, you'd need some sort
0:00:39 > 0:00:42of incredible night vision or the powers of a superhero.
0:00:43 > 0:00:45'A superhero like Daredevil!
0:00:45 > 0:00:49'Though blind, Daredevil's incredible sonar sense gives him
0:00:49 > 0:00:52'powers far beyond sighted people.'
0:00:52 > 0:00:54Well, I've heard of a real-life Daredevil!
0:00:54 > 0:00:56A blind man who defies science!
0:00:56 > 0:00:58A man who uses an ability that we thought
0:00:58 > 0:01:01only existed in the animal kingdom.
0:01:02 > 0:01:06After losing his sight completely as a child,
0:01:06 > 0:01:08American Juan Ruiz did something amazing.
0:01:08 > 0:01:12With incredible determination, he set out to teach himself
0:01:12 > 0:01:16to see with sound just like bats and dolphins do.
0:01:16 > 0:01:19Juan's astonishing ability is way beyond human capabilities,
0:01:19 > 0:01:22so is Juan a real-life superhuman?
0:01:23 > 0:01:26And here he is. It's a pleasure to meet you.
0:01:26 > 0:01:28It's a great pleasure to meet you as well.
0:01:28 > 0:01:31Can I turn off this light as ask you to navigate us
0:01:31 > 0:01:32out of here?
0:01:32 > 0:01:34I had no idea you even had a light.
0:01:34 > 0:01:36Because you're completely blind, is that right?
0:01:36 > 0:01:38That's correct. I do not see anything at all
0:01:38 > 0:01:40because what I have actually done is
0:01:40 > 0:01:44I have trained my brain to see by using sound.
0:01:44 > 0:01:45That's absolutely incredible.
0:01:45 > 0:01:48- I'm going to turn it off now. There we go.- All right!
0:01:48 > 0:01:51- Now you get us out of here. - Excellent! Follow me.- OK.
0:01:54 > 0:01:57- Juan, you've got me back outside again. That's good news.- Sure is.
0:01:57 > 0:02:00Now what I'd like to do is I'd like to ask you to take part
0:02:00 > 0:02:03in three super tests to test your superhuman abilities.
0:02:03 > 0:02:05A superhuman versus...
0:02:05 > 0:02:08Well, it's me...versus me. You on for that?
0:02:08 > 0:02:10Oh, I'm excited! Let's do it!
0:02:10 > 0:02:12- OK, let's get started.- Let's do it.
0:02:12 > 0:02:15This is Dr Megan John, she's an expedition doctor
0:02:15 > 0:02:19and has kept people alive in some of the most dangerous environments.
0:02:21 > 0:02:24She's devised three super tests to discover how Tim
0:02:24 > 0:02:27and Juan react differently without their eyesight.
0:02:30 > 0:02:33For Super Test One, Dr Megan has brought Tim
0:02:33 > 0:02:35and Juan to Los Angeles, California.
0:02:35 > 0:02:36It's the home of Hollywood,
0:02:36 > 0:02:39where the biggest movies on the planet are made,
0:02:39 > 0:02:41and a city where the sun always shines.
0:02:41 > 0:02:44But it's fair to say that this test has a real dark side.
0:02:44 > 0:02:46So, guys, for my Super Test One,
0:02:46 > 0:02:50I've brought you to this real life Hollywood film studio.
0:02:50 > 0:02:52- Wow!- Awesome
0:02:52 > 0:02:55I want to see how the two of you manage to navigate your way around
0:02:55 > 0:02:57- in complete darkness. - Oh, that sounds easy!
0:02:57 > 0:02:59It's not quite as simple as it seems.
0:02:59 > 0:03:00Oh, it never is.
0:03:02 > 0:03:03It certainly isn't,
0:03:03 > 0:03:06because they'll have to get from one side of this special Hollywood set
0:03:06 > 0:03:10to the other in total darkness and without touching any of the props.
0:03:10 > 0:03:14Moving around in complete darkness can be extremely dangerous.
0:03:14 > 0:03:18Now there aren't any Hollywood super-villains hiding in there,
0:03:18 > 0:03:21but any obstacle in the dark can do serious damage
0:03:21 > 0:03:25and these props are almost impossible to avoid without sight.
0:03:25 > 0:03:28Some are low while others are hanging from the ceiling.
0:03:28 > 0:03:31Tim and Juan are at risk of tripping and falling,
0:03:31 > 0:03:34so they'll need helmets and padding.
0:03:34 > 0:03:37But that's not all Dr Megan is going to ask them to wear.
0:03:37 > 0:03:40OK, so, Tim, so when you've put on all your safety equipment,
0:03:40 > 0:03:42I'm going to be fitting the two of you with your blindfolds.
0:03:42 > 0:03:45Oh, but I have my permanent blindfold on already.
0:03:45 > 0:03:47Unfortunately, this is a scientific experiment
0:03:47 > 0:03:50so anything I do to Tim, I also need to do the same to you.
0:03:50 > 0:03:51All right, that makes sense.
0:03:51 > 0:03:54I'm going to be recording three pieces of data. I'll be timing you,
0:03:54 > 0:03:57seeing how long it takes you to complete the challenge,
0:03:57 > 0:04:00I'll also be recording how many objects you knock into.
0:04:00 > 0:04:04And finally, I'm interested in seeing how hard your brain is having to work
0:04:04 > 0:04:05to complete this test,
0:04:05 > 0:04:08so I'll be fitting the two of you with these special headbands
0:04:08 > 0:04:11which will record the electrical waves that your brain sends out.
0:04:11 > 0:04:14- Are you both ready to go?- Yes!- Yeah! Yeah, let's do it.- OK.
0:04:15 > 0:04:19When you're plunged into total darkness, your first instinct
0:04:19 > 0:04:23is to use touch to navigate, so you'll stretch out your arms
0:04:23 > 0:04:26to feel for things in front of you. You'll become scared
0:04:26 > 0:04:29and disorientated and you'll walk in circles.
0:04:29 > 0:04:32Because your eyes help you balance, you'll begin to walk
0:04:32 > 0:04:36in a crouching position to be lower to the ground in case you fall.
0:04:36 > 0:04:38You could fall or bump into things
0:04:38 > 0:04:41and get a nasty cut or bruise yourself on a hard object.
0:04:41 > 0:04:44The worst case is that you could hit your head,
0:04:44 > 0:04:47and develop concussion and concussion can be fatal.
0:04:47 > 0:04:50Because there's no light in the room, we're filming this test
0:04:50 > 0:04:53with special cameras that can see in the dark.
0:04:53 > 0:04:56OK, Tim, in you go.
0:04:56 > 0:05:00OK, Super Test One, find the curtain.
0:05:00 > 0:05:03Oh! Oh! That's a funny old thing.
0:05:03 > 0:05:06That's, er, obviously an inflatable thing.
0:05:06 > 0:05:08Not a good start for Tim who enters the room
0:05:08 > 0:05:11and immediately collides with an inflatable column.
0:05:11 > 0:05:12Ow! That's something else.
0:05:12 > 0:05:16So he's put his arms out and he's feeling his way around
0:05:16 > 0:05:19to try and give him some more idea of where he's going.
0:05:19 > 0:05:21Going forward now.
0:05:21 > 0:05:23Ow! Something else! What was that?
0:05:23 > 0:05:24I'm hearing something
0:05:24 > 0:05:26Oh, now that's gone.
0:05:26 > 0:05:29Because Tim can't see, he's relying more heavily
0:05:29 > 0:05:32on his ears picking up sounds from the room around him.
0:05:32 > 0:05:36Sound reaches the ears in waves which are channelled inside your ear
0:05:36 > 0:05:39by the bit on the outside called the pinna.
0:05:40 > 0:05:41Once inside your ear,
0:05:41 > 0:05:45the sound waves hit your eardrum, making it vibrate.
0:05:45 > 0:05:48These vibrations travel to your inner ear,
0:05:48 > 0:05:51which sends signals to the brain.
0:05:51 > 0:05:55Your brain then works out what the sound is and where it's coming from.
0:05:55 > 0:05:58Sound waves bounce off hard surfaces,
0:05:58 > 0:05:59which is why we can hear echoes,
0:05:59 > 0:06:01especially in places with hard walls.
0:06:04 > 0:06:06So how is Tim getting on without his sight?
0:06:06 > 0:06:09There's something there. That's another one of those crazy columns.
0:06:09 > 0:06:12He's looking a little bit confused.
0:06:12 > 0:06:14That can't be the first column, can it?
0:06:14 > 0:06:16He's quite disorientated by this experiment.
0:06:16 > 0:06:19Oh, that's something there.
0:06:19 > 0:06:23That's a small...foam...cube!
0:06:23 > 0:06:26Tim is supposed to be avoiding the obstacles,
0:06:26 > 0:06:28but instead he's touching all of them.
0:06:28 > 0:06:29What's that?
0:06:29 > 0:06:31Ah! That's balloons!
0:06:31 > 0:06:34He's also lowering his centre of gravity, spreading his legs out,
0:06:34 > 0:06:36to keep himself stable.
0:06:36 > 0:06:39Ah, that's a corner. I've hit a corner in the room.
0:06:39 > 0:06:41Right, that's not a good sign.
0:06:41 > 0:06:43Let's just try and let's try and work this out.
0:06:43 > 0:06:45So, Tim's really disorientated,
0:06:45 > 0:06:48he's actually quite near the finish point but he's got no idea any more,
0:06:48 > 0:06:52so he's kind of walking back into the middle of the room.
0:06:52 > 0:06:55I could just be going round in circles.
0:06:55 > 0:06:58Your eyesight is extremely important for you to work out
0:06:58 > 0:07:01where you are and which direction you're going in.
0:07:01 > 0:07:05As you pass objects, your eyes send images to the visual cortex
0:07:05 > 0:07:09in your brain, where they are placed on a mental map.
0:07:09 > 0:07:12When you turn left or right, your brain uses objects you can see,
0:07:12 > 0:07:15to work out how much you've turned.
0:07:15 > 0:07:17But without your eyesight, your brain finds it difficult
0:07:17 > 0:07:21to tell how far you have turned or whether you have been there before.
0:07:23 > 0:07:26Hmm! I wonder if Tim's managed to get his bearings yet?
0:07:26 > 0:07:28That's another wall, that's not a curtain.
0:07:28 > 0:07:29Ow!
0:07:29 > 0:07:31There's that rock again, hang on.
0:07:32 > 0:07:36Tim is now back at the start, but will he even notice?
0:07:36 > 0:07:38There's another...
0:07:38 > 0:07:44Either that's the same rock again or I really am going round in circles.
0:07:44 > 0:07:48He's now right back at the beginning where he started from.
0:07:48 > 0:07:50Now this is where I came in.
0:07:50 > 0:07:52I think he's probably feeling a bit disappointed.
0:07:52 > 0:07:58OK, let's try this again. I'm going round the rock...forward.
0:07:58 > 0:08:01The longer he goes without hitting an obstacle,
0:08:01 > 0:08:03because he knows I've put obstacles in there,
0:08:03 > 0:08:06it's almost like the more apprehensive he gets.
0:08:06 > 0:08:07There's the ball.
0:08:07 > 0:08:11When he reaches an obstacle, particularly one he's seen before,
0:08:11 > 0:08:13his brainwave activity does go a bit lower.
0:08:13 > 0:08:15The longer Tim's in the room,
0:08:15 > 0:08:18the more this becomes an experiment about how good his memory is,
0:08:18 > 0:08:21rather than how good he is at using his senses.
0:08:21 > 0:08:23Oh, wow! That's a tree. I've not found that before.
0:08:23 > 0:08:26You can see that as soon as that happened,
0:08:26 > 0:08:27brainwave activity went up.
0:08:27 > 0:08:30As soon as he knows it's a safe thing that's not going to hurt him,
0:08:30 > 0:08:32it relaxes back down again.
0:08:32 > 0:08:33TIM EXHALES
0:08:35 > 0:08:36Oh, that's new as well.
0:08:36 > 0:08:38That's a fairly solid object.
0:08:38 > 0:08:41When he hit the rock, there as a peak in brainwave activity.
0:08:43 > 0:08:46He's reached a road sign, there was another peak.
0:08:46 > 0:08:48OK, so this is an area we've not been in before.
0:08:48 > 0:08:53He doesn't realise it, but the finish is just one step to his left now.
0:08:55 > 0:08:56That's a curtain!
0:08:56 > 0:08:58He's just hit the end, so I'm just going to get him out.
0:08:58 > 0:09:00Now is that a different curtain?
0:09:00 > 0:09:01Tim, it's the right curtain!
0:09:01 > 0:09:04- It's the right curtain! - It's the right curtain!
0:09:04 > 0:09:06I've made it! I've found the curtain.
0:09:06 > 0:09:07- You've made it! - How exciting is that?!
0:09:07 > 0:09:09I think I went round in circles a lot.
0:09:09 > 0:09:12- I'm going to take your blindfold off, OK?- OK.
0:09:12 > 0:09:14Now the bright lights will be a bit much for you to get used to.
0:09:14 > 0:09:16Might have to take a second on that.
0:09:16 > 0:09:18- Keep your eyes closed for a second.- Ow!
0:09:18 > 0:09:19That's not very nice.
0:09:19 > 0:09:22Oh, wow! That's really bright, isn't it?
0:09:23 > 0:09:24Oh-h!
0:09:26 > 0:09:30Oh, I'm there. There we go, I can see you now.
0:09:30 > 0:09:32Tim did indeed walk around in circles.
0:09:32 > 0:09:34He took seven minutes to cross the room and touched 30 objects.
0:09:34 > 0:09:36'Oh, that's new as well!'
0:09:36 > 0:09:39The results of Megan's mind-band showed that Tim found
0:09:39 > 0:09:43the whole experience challenging and disorientating.
0:09:43 > 0:09:44Juan is up next.
0:09:44 > 0:09:46Will he be able to use his amazing abilities
0:09:46 > 0:09:48to complete this challenge?
0:09:48 > 0:09:49OK, in you go!
0:09:50 > 0:09:53All right, well, I know two things about what I'm about to do,
0:09:53 > 0:09:56and that is I'm going through one curtain
0:09:56 > 0:09:59and then coming out on the other end through another curtain.
0:10:06 > 0:10:09Immediately Juan starts making a clicking noise.
0:10:09 > 0:10:12And, incredibly, ducks under a lampshade
0:10:12 > 0:10:16as if he could see it, but he can't!
0:10:16 > 0:10:19Is this noise something to do with Juan's Super Human skills?
0:10:19 > 0:10:22Now remember, Juan hasn't even seen any of these obstacles either.
0:10:22 > 0:10:25Tim was frightened that the obstacles were going to hurt him.
0:10:25 > 0:10:28Juan's walking around quite quickly
0:10:28 > 0:10:30That doesn't sound like a curtain!
0:10:30 > 0:10:32Juan cannot see the wall and has not touched it,
0:10:32 > 0:10:35yet he knows it's not a curtain.
0:10:35 > 0:10:36How is he doing this?
0:10:36 > 0:10:40You'll notice that the most obvious difference between his approach
0:10:40 > 0:10:43and Tim's is that Tim immediately put his hands up to protect himself.
0:10:43 > 0:10:47Juan's got his hands down by his side and is very relaxed.
0:10:47 > 0:10:49Fine, fine, fine...
0:10:53 > 0:10:56He's just made the curtain, I'm going to go and get him out.
0:10:56 > 0:11:00Juan completed Super Test One in an incredible 1 minute 50 seconds
0:11:00 > 0:11:03and touched only one object.
0:11:03 > 0:11:07Remember, it took Tim five minutes longer and he touched 30 objects.
0:11:07 > 0:11:11Juan's mindband results show that he found this ridiculously easy.
0:11:11 > 0:11:13So how is he doing it?
0:11:13 > 0:11:16When you stepped into the room you paused for a moment
0:11:16 > 0:11:19and started making these funny noises. What was that?
0:11:19 > 0:11:22I was clicking, I was making a click sound, just...
0:11:22 > 0:11:23CLICKS
0:11:23 > 0:11:25..so that I could get my orientation
0:11:25 > 0:11:28because that click bounces off the walls
0:11:28 > 0:11:32that are all over the room so that I get the dimensions of the room.
0:11:33 > 0:11:36What Juan is describing is something called echolocation
0:11:36 > 0:11:39and it's a way of using sound waves to see
0:11:39 > 0:11:42just as bats and dolphins do.
0:11:42 > 0:11:44When you make a noise, the sound waves come out of your mouth
0:11:44 > 0:11:47and spread all around you.
0:11:47 > 0:11:50They hit objects and are bounced back to your ears.
0:11:50 > 0:11:53Like this - these are called echoes.
0:11:53 > 0:11:56Your brain usually ignores the echoes from your own voice,
0:11:56 > 0:11:59but Juan's brain is different.
0:11:59 > 0:12:02Juan has learnt to use echoes from his clicking noise
0:12:02 > 0:12:06to work out where objects are and what shape they are.
0:12:06 > 0:12:09Every click allows Juan to see an object with his ears
0:12:09 > 0:12:12but only while the echo lasts.
0:12:14 > 0:12:19Being in the dark for even ten minutes really affected my eyes.
0:12:19 > 0:12:23So imagine how your eyes would cope after months in the darkness.
0:12:23 > 0:12:28Tragedy struck 33 miners in Chile, when a tunnel collapsed,
0:12:28 > 0:12:31trapping them 700 metres underground.
0:12:31 > 0:12:34They were sent food and water so they could survive,
0:12:34 > 0:12:38but living in constant darkness can make you feel very depressed.
0:12:38 > 0:12:41The miners needed to keep to a daily routine so they knew
0:12:41 > 0:12:44when to go to bed and when to get up without sunlight.
0:12:44 > 0:12:47They also sang songs to keep their spirits up.
0:12:47 > 0:12:51After two months, rescue teams were able to lift them out.
0:12:51 > 0:12:54The miners wore sunglasses for several days afterwards
0:12:54 > 0:12:57to protect their eyes while they adjusted to the daylight.
0:12:59 > 0:13:03For the second Super Test, Dr Megan has taken Tim and Juan
0:13:03 > 0:13:07out of Hollywood down to one of the busiest piers in the world
0:13:07 > 0:13:10at Santa Monica.
0:13:10 > 0:13:11For my Super Test Two,
0:13:11 > 0:13:14I want to study Juan's echolocating abilities still further.
0:13:14 > 0:13:18So I want to see if the two of you can identify objects
0:13:18 > 0:13:22when you go past them just by using the way they reflect soundwaves.
0:13:22 > 0:13:25And I want to see how you do that in a real live situation.
0:13:29 > 0:13:32In this Super Test, Juan and Tim will have
0:13:32 > 0:13:35to correctly identify five objects on the pier
0:13:35 > 0:13:38and once again they will be blindfolded.
0:13:38 > 0:13:41These objects will be big, small, hard and soft.
0:13:41 > 0:13:43So Tim is going to need some help.
0:13:44 > 0:13:46Go ahead and click.
0:13:53 > 0:13:54That's really gone
0:13:54 > 0:13:57and it's not just because it's down below, I can really...
0:13:57 > 0:13:59It's gone, it's not there.
0:13:59 > 0:14:01It's not at the face level where it's at now.
0:14:01 > 0:14:05The sound is not bouncing directly off of it.
0:14:05 > 0:14:08When you are clicking, you really can feel
0:14:08 > 0:14:12that there's something coming back at you but when it's not there,
0:14:12 > 0:14:15I know there's nothing coming back at me
0:14:15 > 0:14:17Tim's beginning to get the hang of it
0:14:17 > 0:14:20but there is still a great danger that he will get a nasty bump
0:14:20 > 0:14:24from a hard object. There's enough noise and bustle out there
0:14:24 > 0:14:26to really confuse him.
0:14:26 > 0:14:29From Super Test One, I saw how incredible, Juan,
0:14:29 > 0:14:31your ability to avoid bumping into things was,
0:14:31 > 0:14:34so I don't think you need to do this test in protective gear.
0:14:34 > 0:14:38Tim. You on the other hand - full safety equipment.
0:14:38 > 0:14:40OK.
0:14:40 > 0:14:45We've asked Tim and Juan to identify exactly the same objects
0:14:45 > 0:14:47along one of the busiest piers in the world,
0:14:47 > 0:14:50just from the way they sound. Tim is up first.
0:14:50 > 0:14:53Stop where you are. OK, now slightly to your right
0:14:53 > 0:14:56is the object I'd like you to try and identify.
0:14:59 > 0:15:01Yeah, that's there.
0:15:01 > 0:15:04I've touched that with my elbow.
0:15:04 > 0:15:07Unable to find the position quick enough,
0:15:07 > 0:15:10Tim has touched the bin before he's even clicked.
0:15:11 > 0:15:15Tim will not be allowed to guess this one.
0:15:15 > 0:15:18Normally, to identify an object you'd use sight.
0:15:18 > 0:15:22As well as that you'd use your other senses - smell, touch and hearing.
0:15:22 > 0:15:25I've taken away his sight which is the easiest one to use,
0:15:25 > 0:15:28so Tim's exhibiting exactly what I would expect
0:15:28 > 0:15:29a normal human reaction to be.
0:15:29 > 0:15:31To try to utilise all the other senses.
0:15:31 > 0:15:34He can't help but put his hands out
0:15:34 > 0:15:37to use feel and touch to give him an idea.
0:15:37 > 0:15:42Who can blame him? Touch is one of our most important senses after all.
0:15:43 > 0:15:47Your skin is covered in nerve cells called receptors
0:15:47 > 0:15:48that send messages to your brain
0:15:48 > 0:15:51whenever your skin touches something.
0:15:51 > 0:15:53There are three types of receptors.
0:15:53 > 0:15:57Some for temperature, some for pressure and some for pain.
0:15:57 > 0:15:59When you touch an object with your fingers,
0:15:59 > 0:16:03your pressure sensors can help you decide if is hard or soft
0:16:03 > 0:16:04and what shape it is.
0:16:04 > 0:16:08Your temperature sensors tell you if the object is hot or cold.
0:16:08 > 0:16:10This is how you can tell what things are made of.
0:16:13 > 0:16:15Now it's time for Juan's go at the bin.
0:16:15 > 0:16:17Even though he is totally blind,
0:16:17 > 0:16:19Juan has agreed to wear the blindfold again,
0:16:19 > 0:16:23just to keep the test the same for him and Tim.
0:16:25 > 0:16:28Oh, my gosh. All right so let's listen to this thing,
0:16:28 > 0:16:30see what it is.
0:16:30 > 0:16:32Ooh, wow.
0:16:32 > 0:16:34Juan immediately finds the object
0:16:34 > 0:16:36while it is still almost half a metre away from him.
0:16:36 > 0:16:38When Tim was doing this, he was exhibiting exactly
0:16:38 > 0:16:40what I'd expect a human to do to.
0:16:40 > 0:16:42Putting his hands out, he couldn't help himself
0:16:42 > 0:16:43but try to use some touch.
0:16:43 > 0:16:45A trash can!
0:16:45 > 0:16:46Ah!
0:16:46 > 0:16:49It's nice and round and it's got the height of...
0:16:49 > 0:16:50A trash can?
0:16:50 > 0:16:52A trash can, exactly!
0:16:52 > 0:16:54Really impressive, sir.
0:16:54 > 0:16:57Next challenge - a vendor's booth selling t-shirts.
0:17:04 > 0:17:07I've hit something with my head and that's probably not a good sign.
0:17:07 > 0:17:10Once again Tim has collided with the object before finding it
0:17:10 > 0:17:12with his clicks.
0:17:12 > 0:17:14This doesn't seem as solid.
0:17:14 > 0:17:18Juan's told us that not only can he orientate how large an echo is
0:17:18 > 0:17:22using his echolocation techniques, but the density.
0:17:22 > 0:17:24That is, how hard it is or how soft it is
0:17:24 > 0:17:27changes the way the sound wave is reflected back
0:17:27 > 0:17:29OK, that's the other edge. So there's edges here.
0:17:29 > 0:17:31Oh no, maybe.
0:17:31 > 0:17:35It's difficult because it seems to be... The sound isn't...
0:17:35 > 0:17:38OK, Tim, let's move on now from this one.
0:17:38 > 0:17:41Tim didn't manage to identify this one either.
0:17:41 > 0:17:44How will Juan deal with such a large soft object?
0:17:44 > 0:17:46OK, stop there.
0:17:46 > 0:17:49Yes I hear it, so let's see. Let's study this obstacle.
0:17:51 > 0:17:53Well, it's taller than me
0:17:53 > 0:17:55but that's not too hard because I'm rather short.
0:17:55 > 0:17:59This time Juan hears the object while he is over a metre away.
0:17:59 > 0:18:02So straight away before I positioned him near it he said,
0:18:02 > 0:18:04"Oh, yeah. I hear it."
0:18:04 > 0:18:08Now, it's not making any noise, it's him hearing back those clicks.
0:18:08 > 0:18:14See, this object is interesting because it's not very solid.
0:18:15 > 0:18:19Different objects reflect sound waves in different ways.
0:18:19 > 0:18:20If you were to tap on a box,
0:18:20 > 0:18:23you could tell if it was hollow or solid,
0:18:23 > 0:18:27or if it was made of metal or wood simply by the sound it made.
0:18:27 > 0:18:30Amazingly, Juan's brain is able to do this just by using
0:18:30 > 0:18:31the echoes of his click.
0:18:31 > 0:18:35Juan's brain detects how the sound in the echo has changed
0:18:35 > 0:18:38to work out what the objects are made of.
0:18:38 > 0:18:42Hard objects reflect more sound than soft objects
0:18:42 > 0:18:45and Juan's brain can detect the tiniest changes.
0:18:48 > 0:18:53I would... You know, I would have to say this is a vendor's booth.
0:18:53 > 0:18:55Amazing!
0:18:55 > 0:18:58Juan is of course completely right, again.
0:18:59 > 0:19:03About a foot in front of you is the next object I'd like you to identify.
0:19:03 > 0:19:07Because Tim can't see, he is finding it hard to judge how far away
0:19:07 > 0:19:08the objects are in this test.
0:19:08 > 0:19:11Will he be able to avoid touching this one?
0:19:11 > 0:19:14CLICKS
0:19:14 > 0:19:16Now of course you have touched it a few times so.
0:19:16 > 0:19:22Yeah, I can feel that there is something like, like leaves.
0:19:22 > 0:19:25Maybe like plastic crazy foliage.
0:19:25 > 0:19:29I don't know how to do this so my ability to get where,
0:19:29 > 0:19:30how close it is, is quite difficult
0:19:30 > 0:19:33so sometimes I nudge the object when I don't mean to.
0:19:33 > 0:19:34Like I've just done it there.
0:19:34 > 0:19:37And of course if you nudge the object you get...
0:19:37 > 0:19:39I get some information about it.
0:19:39 > 0:19:42Step forward. Again, again, again. And stop there.
0:19:42 > 0:19:46It's just about 30 centimetres in front.
0:19:46 > 0:19:49Let's see.
0:19:52 > 0:19:54It sounds like a bush.
0:19:54 > 0:19:59Right, Juan, you have made my test look too easy!
0:19:59 > 0:20:02The next object is a fire hydrant
0:20:02 > 0:20:04and Tim has found it with his stick.
0:20:04 > 0:20:05There's something there.
0:20:05 > 0:20:09But can he work out what it is with his click?
0:20:11 > 0:20:13CLICKS
0:20:16 > 0:20:18His hands are all over it. He can't help it!
0:20:18 > 0:20:22He won't prove anything in this test, even if he guesses what it is.
0:20:22 > 0:20:24Some sort of post.
0:20:24 > 0:20:27Time for Juan to try - remember, he uses just his hearing
0:20:27 > 0:20:31and he doesn't touch the object so it's a little trickier for him.
0:20:31 > 0:20:33Oh, wow!
0:20:35 > 0:20:37I would say this is a chair.
0:20:37 > 0:20:40OK, so about the height of a chair. Right, well.
0:20:40 > 0:20:44It's not just the height, because the height comes up to about here.
0:20:44 > 0:20:46But then there's something here that is more flat
0:20:46 > 0:20:47and then the back goes up.
0:20:47 > 0:20:49OK, all right.
0:20:49 > 0:20:50So I think it's a chair.
0:20:50 > 0:20:53Because Juan uses sound waves to create an image,
0:20:53 > 0:20:57he thinks that the barrier behind the post and the box next to it
0:20:57 > 0:20:59are all part of the same thing,
0:20:59 > 0:21:02which does actually resemble the shape of a chair.
0:21:02 > 0:21:04So I think we can let him off with this one.
0:21:04 > 0:21:05Time for the next object.
0:21:12 > 0:21:14This is really interesting,
0:21:14 > 0:21:17cos although it's right in front of him, he's moved to the side.
0:21:17 > 0:21:19I'm not sure he's got any idea of that.
0:21:19 > 0:21:21Tim's shoulder has just touched the lamp post.
0:21:21 > 0:21:25He's not going to be allowed to guess this one either now.
0:21:25 > 0:21:29Juan's go next, but will the shape of the railing put him off again?
0:21:31 > 0:21:34Well, it's very thin,
0:21:34 > 0:21:39and it's right next to the railing right here.
0:21:39 > 0:21:42But I can put my hands straight through here right behind it.
0:21:42 > 0:21:46When Tim was putting things forward he was just touching everything.
0:21:46 > 0:21:50Juan was able to demonstrate beautifully without touching a thing.
0:21:52 > 0:21:55I would say it's something like a light pole.
0:21:55 > 0:21:58I just have no idea but I'll say a light pole.
0:21:58 > 0:22:00You have no idea but you're guessing a lamp post?
0:22:00 > 0:22:01It's some type of pole.
0:22:01 > 0:22:06Juan has guessed correctly an incredible four out of five objects
0:22:06 > 0:22:09on Santa Monica Pier using only sound.
0:22:09 > 0:22:11It sounds like a bush.
0:22:11 > 0:22:13And although Tim made a great attempt,
0:22:13 > 0:22:16he couldn't get over his instinct to touch.
0:22:16 > 0:22:20His hands just got in the way, as did his mouth.
0:22:20 > 0:22:24I was amazed at how well Juan moved about on the pier without sight.
0:22:24 > 0:22:27But there are some people who spend their whole lives
0:22:27 > 0:22:29in a dark environment.
0:22:29 > 0:22:32The Penan people live in the rainforests of Malaysia
0:22:32 > 0:22:33in South East Asia.
0:22:33 > 0:22:37The giant trees have very thick top branches and leaves
0:22:37 > 0:22:39which block out the
0:22:39 > 0:22:42sun, so the forest is very dark even during the day.
0:22:42 > 0:22:46But the tribe are perfectly adapted to finding their way around
0:22:46 > 0:22:49so they don't get lost.
0:22:49 > 0:22:52They can even hunt animals in the dark, the lack of light
0:22:52 > 0:22:55and noise helps them track their prey more easily.
0:22:55 > 0:22:59Their senses can detect even the smallest changes in light,
0:22:59 > 0:23:03sound, smell and temperature of the forest which outsiders can't.
0:23:04 > 0:23:07Doctor Megan's Super Test Three is taking place
0:23:07 > 0:23:09in Irvine Park, California.
0:23:09 > 0:23:13And it's going to be one of the most dangerous Super Tests yet.
0:23:13 > 0:23:18Juan has told me he can do something absolutely incredible.
0:23:18 > 0:23:20He can mountain bike without sight.
0:23:20 > 0:23:23Wow, that's unreal. That's absolutely incredible.
0:23:23 > 0:23:26- Completely terrifying. - It's exhilarating for sure.
0:23:26 > 0:23:29Mountain biking is all about riding tough bikes
0:23:29 > 0:23:31over even tougher terrain.
0:23:31 > 0:23:34It requires endurance, strength and balance.
0:23:34 > 0:23:37Risk of injury from falls and collisions is high
0:23:37 > 0:23:40in the sport of mountain biking
0:23:40 > 0:23:43from minor wounds to serious damage to the head and spine.
0:23:43 > 0:23:46Even sighted mountain biking can be very dangerous.
0:23:46 > 0:23:50If you were to fall off you could cut yourself, break bones,
0:23:50 > 0:23:51even knock yourselves out.
0:23:51 > 0:23:54So I've had to take a lot of safety precautions today.
0:23:54 > 0:23:58I've got Robin, an expert mountain biker who'll be leading
0:23:58 > 0:23:59your way down the trail.
0:23:59 > 0:24:04I've got Corrie with all her medical equipment and expertise on standby.
0:24:04 > 0:24:06And Tim, because you've not done this before,
0:24:06 > 0:24:10- I'm going to ask you to practise away from the trail first.- OK.
0:24:10 > 0:24:12- So, guys, let's give it a go. - Let's go!
0:24:12 > 0:24:16Worried that Tim will seriously injure himself,
0:24:16 > 0:24:20Dr Megan asks two members of the film crew to run alongside him.
0:24:20 > 0:24:22But even with a team of people helping,
0:24:22 > 0:24:23Tim almost collides with a tree.
0:24:26 > 0:24:29I don't think it would be safe for Tim to do the trail course
0:24:29 > 0:24:31- that we've set up for you. - It doesn't sound like it.
0:24:31 > 0:24:34- It seems like he'll need a lot more practice.- I agree.
0:24:34 > 0:24:38This super test is just too dangerous for Tim to try
0:24:38 > 0:24:41so it looks like Juan will be doing it on his own!
0:24:44 > 0:24:48In this test, Juan will be cycling blindfolded for 1 km
0:24:48 > 0:24:52along the twists, turns and steep drops of this mountain forest track.
0:24:52 > 0:24:55Using his ears, he will be following the bike in front
0:24:55 > 0:24:58which will be making a loud clicking sound.
0:24:58 > 0:25:01Remember, Juan is totally blind,
0:25:01 > 0:25:03so the blindfold makes no difference to him.
0:25:03 > 0:25:07It's simply being worn to keep him under test conditions.
0:25:08 > 0:25:12Cycling blindfolded, downhill is incredibly dangerous.
0:25:12 > 0:25:13Actually, totally impossible.
0:25:13 > 0:25:16Let's face it - you will come off your bike.
0:25:16 > 0:25:19When this happens you could cut or bruise yourself.
0:25:19 > 0:25:21You could even break a bone. If you hit a tree at speed,
0:25:21 > 0:25:23you could break your neck or back,
0:25:23 > 0:25:27or you might fall off a steep slope and crack your head on a rock.
0:25:27 > 0:25:30Serious head injuries are fatal.
0:25:30 > 0:25:32OK, so here we are at the start line.
0:25:32 > 0:25:36It's a really tricky course. I can't wait to see how you get on.
0:25:36 > 0:25:37- Are you ready to go?- Ready.
0:25:37 > 0:25:39Off you of go.
0:25:42 > 0:25:44Let's go!
0:25:44 > 0:25:47Juan sets off down the hazardous track completely blind.
0:25:47 > 0:25:49For a sighted person,
0:25:49 > 0:25:52even attempting this blindfolded would be unthinkable.
0:25:52 > 0:25:55Although he is listening out for the lead bike,
0:25:55 > 0:25:59he is still using his own click to help him navigate the course.
0:25:59 > 0:26:01Juan takes the first corner with ease.
0:26:01 > 0:26:05But remember this is just the first of many corners and dips.
0:26:05 > 0:26:08This course could be lethal.
0:26:08 > 0:26:10As Juan begins to pick up speed,
0:26:10 > 0:26:12it's hard to believe that he cannot see anything.
0:26:12 > 0:26:17He is doing this incredible feat using only his hearing.
0:26:17 > 0:26:19As he approaches a hairpin bend,
0:26:19 > 0:26:21Juan almost comes off the track
0:26:21 > 0:26:22but he quickly recovers.
0:26:24 > 0:26:27What Juan is doing would be too dangerous for someone
0:26:27 > 0:26:32without his skill and experience to try. This is incredible!
0:26:34 > 0:26:38Another tight corner and Juan takes it with ease.
0:26:42 > 0:26:44Watching how effortlessly Juan does this,
0:26:44 > 0:26:47it's hard to believe that he can't see.
0:26:48 > 0:26:50This road may be straight
0:26:50 > 0:26:53but there's a serious drop to Juan's right!
0:27:00 > 0:27:03He's on the home straight now and Dr Megan and Tim
0:27:03 > 0:27:05are waiting to cheer him over the finish line.
0:27:12 > 0:27:14- Wow, that's amazing! - Congratulations!
0:27:14 > 0:27:17Juan has finished this course in just over three minutes,
0:27:17 > 0:27:21making his average speed a very impressive 20 kilometres an hour.
0:27:24 > 0:27:27Juan Ruiz can identify the world around him by seeing with sound.
0:27:27 > 0:27:32Incredibly, he does this even in the most extreme conditions.
0:27:32 > 0:27:35There's no doubt he IS Super Human.
0:27:35 > 0:27:38That was simply amazing, what you just did.
0:27:38 > 0:27:42You've developed your hearing to Super Human levels
0:27:42 > 0:27:43with what you do with it.
0:27:43 > 0:27:46I came here to meet a real-life Daredevil.
0:27:46 > 0:27:48I've met him. It's you.
0:27:59 > 0:28:02Subtitles by Red Bee Media Ltd