Transcript for Sewer Kids: Life Inside Bucharest, Romania's Underground Tunnels
We're about to enter a world normally hidden, a true subculture of people living almost entirely underground. The comforts are few and far between, but tonight we're meeting their leader. Here's bob woodruff. Reporter: Look close there, at the bottom of your screen. An entrance to a world most never see. Hundreds of people live in the S sewers. Do you speak English? Yes. Reporter: Do you live in the sewers? Why do you do that? You don't have anywhere to live? It's a hard life. Reporter: But the most startliing sewer dwellers, the kids. An estimated 1,100 of them, homeless. His name is Robert, living underground since he was 9. He tells us the people in the tunnels are his family. Generations of people like Robert have grown up in the sewers. Since 1989, when the communist regime was ended, and the lost boys and girls now joined by a new generation of kids like Robert. Can we go down in the tunnel with you? He tells us it's too dangerous to go down there. Addicts ten feet below injecting heroin. Aren't you afraid? No -- it's no problem. Reporter: But that was just a glimpse of the subculture. To see more and do it safely, they would have to find and get permission from their leader, an elusive man named Bruce lee. They treat him like a king. He's our leader. Reporter: To report the story, we hit the streets with a charity group. The only organization in Romania working with the sewer people. Why are they in the tunnels? They have no other choice. Reporter: Can they live in some kind of shelter? No. They're like a family down there. Reporter: This is a doctor and a social worker. Feels like it's about 75 degrees down here. And it's wet. We're on the lookout for Bruce lee. With silver hair, jingling medals, and dogs, we'll know it's him. Only one guy down here, in bad shape. Strung out on drugs. This is where you actually live down here? It's unbearable. I would say this is probably about 95 degrees. With the humidity, it's about the worst, about the hottest, most uncomfortable place. Oh, my god, unbelievable. Reporter: They provide some medical assistance. The veins were broken. Reporter: What kind of drugs? Heroin. It's like a methamphetamine. Reporter: They have little support from the government. Have you witnessed many people die? Yeah, yeah, yeah, a lot of people die. Reporter: All taking place just steps from the avenues of power. The prime minister goes to work here -- They don't do nothing. Reporter: This is where I went in. The tunnel goes along, there's McDonald's. This tells the story. The poverty, people living underground. It's stunning, I have to say. We visited several tunnels looking for Bruce lee. Rotting clothes serving as beds. How long have you been living here? One year? Yes. Reporter: The police have tried sealing the sewer entrances, but they find another way in. It will never go away? No. Reporter: Finally at dusk, there he was. The man we were looking for. Bruce lee. His large pack of dogs and jingling medals giving him away. Why do children live down here? Translator: They have nowhere to go. Here, they have food and water and heat. Reporter: Do you know everybody down here? Translator: I know them all. I control everything down here. They didn't have anyone to guide them to do good before me. Reporter: He paints his hair. Making you look more crazy gives you more credibility? Translator: They leave me alone. Reporter: You don't have shoes. That's the way I walk around all year. Reporter: What's in the bag? They tell us drugs are a comfort for them. What does it feel like? If you didn't have the bag, do you think you would be able to survive out here? Translator: Yes, no problem. Reporter: How much would it cost me to buy the bag of drugs? $2? And you just get -- really? Do you like it? This guy shows us how it's done. With that, he told us we could go underground. This time, it's very different. Going to go all the way to the bottom. Oh, my god. Lined with people, sitting on the hot pipes. Robert is our guide. This is your home? You live down here? The subway? Watch out for syringes. He leads us to the back, where Bruce lee is holding court. This tunnel has electricity, a fan, even a Christmas tree. Translator: We steal it from the city. Otherwise, we would die on the streets. Reporter: Are there many children living down here? Translator: Yes. During the day, they go in search of the trash for food and whatever they need. Reporter: Bruce lee told us he's raising money to build a new community, a home for all his people. Translator: Here, we're treated like animals. I promised myself if I ever leave the sewers, I would bring them with me. Reporter: For young kids with no prospects and no home, even a dream can be something to cherish. For "Nightline," I'm bob woodruff. The many who live in the tunnels with Bruce lee don't want to live.
This transcript has been automatically generated and may not be 100% accurate.