Transcript for Nik Wallenda on his high-wire stunt in Times Square
So you walked on a high-wire across niagara falls. You walked across the grand canyon without a safety harness, and now you're going to take on times square. Why this location? You know, it really has to do with my family history. My family's first performance in the United States was in 1928, and they walked in Madison square garden, the old garden. Right. I wanted to do something to pay tribute to my family, and that's why I chose this location, times square. Everybody in the world knows what times square is. To be honest I didn't know if I could pull it off. The permissions are insane, but that wire is up. It's happening. Really? Yes. I just -- so you're usually this way or this way. That's one of my biggest concerns for the walk is the lighting is all below it. It's not just steady lighting. You have stuff going like this. What the hell? The worst of the distraction is the entire walk from the traffic in the background of course, moving and the thousands of people below as well as yeah. Those lights are going to be moving like crazy. It's a little stressful and intimidating for sure. It's intimidaing because I can't even get on roller coasters. I'm a scaredy-cat. Emotions will be running particularly high because you'll be performing this stunt with your sister, lijana. That's right. She's making her return to the wire after a devastating fall back in 2017 that really injured her severely, and several other performers. It left you clinging to the wire. Our viewers are seeing that footage right now, but we have kept it out of your view because it's still too difficult for you to actually watch. Your sister, lijana, broke every bone in her face during that fall, and is lucky that she's even alive. Absolutely. It's a blessing, and you say you struggled with fear for the first time ever after that accident, and doubted whether you could even perform anymore. Yeah, you know, interestingly enough after that accident, the day after I had five family members and friends in the hospital. In fact, they weren't sure if my sister was going to survive. She was in a medically induced coma at that point, and I went and I was thinking at that point, you know, I don't know if I can do this anymore, out of respect for these that fell. I was apart of this. I was sort of the leader of that troupe, and I remember my dad coming to me and saying, NIK, I know you have a big walk 30,000 people were going to be there, and I do a lot of motivational speaking from the wire, and my dad said, but I have got your back if you are going to do it. I thought for sure, I wasn't going to walk the wire anymore at that point. Long story short, I got on the wire, and I performed straight through, and took two months off and started training for the big apple circus here in New York City, and I was training for the seven-person pyramid, which is similar, and one less person, but my peripheral view, and I started experiencing PTSD and reliving that accident over and over again. To the point where I was physically shaking on the wire and I went to my wife and said, you know, I don't know if I can do this anymore because I'm so fearful, and my wife said, well, you know, I support you in whatever decision you make, and so I said, well, let me go on and practice a few more days and I practiced two more days and a friend of mine, one of my close friends who walks the wire came up to me and said, you know, NIK, you're not the leader we look up to. Something's wrong. Snap out of it. It took that conversation with me to go, you know, I have to go back to practicing what I preach, which is that fear is lying to us constantly and it's telling us and holding us back from our greatest achievements. We think it's keeping us safe, and it really isn't often. It's keeping us from making that next career move. I'm a gambler, but I would never do anything like that. I'm wondering, what's the motivation for the wallendas? What makes that so -- It's been our family legacy for over 200 years. Think about it. Why do you do this? It's hard for people to understand, but I want to know why you don't do it. I was born doing it. My mom was six months pregnant with me on the wire and still walking. Yeah. I have walked since before I was alive. It's in the DNA. I'm in the process of writing another book right now on overcoming fear because I believe with what I experienced, my hopes are I can help others struggling with fear. You should try standup comedy. That's scary too. Absolutely. You'll write books. Go run for president. There you go. Talk about a high-wire. You would take you over some other people. So this is no easy feat. I don't know if that's a compliment or not. The last person here. This is no easy feat, and this will be incredible. 25 stories above the streets of times square, walking a distance of 1,300 feet, roughly the length of four soccer fields. It's unbelievable. How do you stay focused under this pressure, and do you think your sister will add to your nerve? I haven't slept the last three nights because I have been on the streets rigging this wire to make sure it's perfect for when she steps on it because I want to make sure that everything is just right, and yeah. That is a huge concern that not only do I have these distractions below, but I'll be distracted thinking about her and thinking, if she's okay, and we have to meet in the middle of the wire. We're on the same wire three-quarters of an inch, and she has to sit down and I have to step over. Can't you put a safety net or wire attached? Do you think you can do this forever? There is an eighth generation right now. My niece has nephews that are performing and my sister's son, his dream is to follow in the footsteps.
This transcript has been automatically generated and may not be 100% accurate.