Transcript for ABC News' Matt Gutman explores a cave

With. Remarkable about this is an. What's so remarkable is that I'm. The crouching the whole time. And if you get tired very very quickly. He's basically the constant squad like this trying to make through here imagined it got a backpack with a couple pounds imagine doing it. 5067. Pounds. Who scuba gear no wonder. Whose rescue divers are completely exhausted. You can see how scalpel sharp it looks like some sort of courts which is obviously very hard but. Come sharp it is unimaginable in your head into that each of anything here and that's what's underneath. Living passage ways. So narrow. He's had spewed an if but. Or. Crawl. It imagined it would this underwater. The other issue is. If this thing is. Filled with water. Finding the actual hole is nearly impossible especially when there's no visibility in the water which is why people and to die so often. When can I. Think these. Difficult curtains it's all minerals. Dripping. From the top of the mountain through the the ground. It keeps this constant drip arraigned a lot until after a while now lives and start coming down here. Drops of water. Cisco has come through right now. That camera is Gil hard it is to get any equipment through and he just cut one camera. Could pretty fit guy. Easy to fit through there and you know. Everywhere there is people's. And hazards. Just bang your head on that here at a commission while. The skate goes on. Point about. 550 yards or so. Barely a fraction a cabling. Where the boys are but it gives you sense of how high the spaces can just imagine this whole thing for flooded. How you financial entrance that tiny little entrance when of his abilities absolutely zero it would be nearly impossible and it's one of the reasons. Now for the divers and we've been talking through our. So one now yeah he's gotten completely exhausted. From doing here's here's another issue. Their sudden. Turns. Hard to navigate. Go ahead it's also well who knew what it's like a team but there's a clean bottom here which is very slippery. Making navigation even. And more difficult. Here's a here's a big chamber right here this is kind of. Well there's of that this is kind of what they talk about when there's a chambers who could be a really narrow tunnel for quite a ways. And then it opens up to this. The shootings you're probably twenty feet tall when he behind conceit is that lag thanks hang an off. He tickled curtains they're minerals that are dripping. For. Thousands and thousands of years and there's a Batman there in. Again you know I'm I'm carrying a backpack that probably weighs 1520. Pounds Max. But Pia the rescuers and all those people involved in this rescue. Have pacts with them that way. Dozens and dozens of counselors can imagine how hard it is also. Mean we're in a pretty oxygen rich environment the only people in here. But in that Kate because they Havel that pumping equipment and because of some humans. They've essentially consumed Robert is the director and the camera is its. Are to navigate but all those divers and rigidity or 400 people in McCain wants stable consumed a tremendous amount of oxygen in there. And down. Oxygen level in that cave is about 17%. Which is about the amount of oxygen in the aired that you exhale. That. After taking a breath. Parts of town OK to just imagine just for 12. Imagine going from the big cavern like this. There's plenty of space in your diving and it's filled to the brim and then. Somehow trying to navigate without being able to see to find the hole here it's down there. And there's a turn to the left which shows right now. Yeah this is an example. These crash and this is an example thank you spaces of Robert can get to that spot their. Among pre small guy who pretty small guy and I can't imagine having to go through. Some at this with gas tanks under water trying to help kids get through but this is the only through in this particular tunnel. Pretty dirty. I don't think Roberts commute to get in there. This is very much what it's like for the divers. To get through. Because he go through a really really tight space. And you find big space that allows you to recoup. Get a little rest take a breather. Anyway this is imagine doing this we've done effort. Probably for five minutes since we've been rolling on this live stream. And we've probably navigated so far. Now 5060 yards through the tunnel and that's a tenth of this particular tunnel but it's something like a hundredth. Of the total tunnel that these divers are doing. Imagine doing that again and again that's what they're going to be doing as they extract these kids. Come for the next several days America being in a cage just outside of may site Thailand. And I hope you keep watching and keep your fingers crossed for those little boys and all the rescuers.

This transcript has been automatically generated and may not be 100% accurate.