11:00 p.m.: One final hug for Nik from his wife and this highly-anticipated night is over.
10:58 p.m.: Nik says, "I always tell people that what my great-grandfather passed on from generation to generation is to not give up."
10:56 p.m.: Nik says, "It hasn't sunk in yet. I'm grinning from ear to ear. This is something I've played over and over in my mind for the past 20 years. It's surreal. I'm really blessed to be here."
10:55 p.m.: Hannah Storm asks: "How do you ever top what you did tonight?" Nik says he's already secure the permits to walk across the Grand Canyon. Wow.
10:53 p.m.: The one person who's not there tonight is his grandmom because she was too nervous to walk. Nik promised that she'd be the first person he called and he keeps his promise.
10:46 p.m.: Nik's dad tells his son "I'm very proud of you. You made history and you made the family proud … I'm thrilled you made it to the other side."
10:45 p.m.: Josh Elliott asks what the most surprising thing about the walk was and he says the mist and the winds.
10:43 p.m.: "Welcome to Canada. May I see your passport, please?" Nik pulls his out of a small pouch. They ask him what his purpose of his trip to Canada is and he says "to inspire people all over the world."
10:42 p.m.: Sam Champion is with Nik's wife. She says "I love him so much. I'm just so proud of my husband and so inspired by him."
10:42 p.m.: He did it! Nik Wallenda walks 1,500 feet, becoming the first person to traverse Niagara Falls on a high wire. It took him just over 25 minutes.
10:41 p.m.: Nik's Uncle Mike is holding this side of the wire.
10:40 p.m.: Nik takes one hand off and fists pumps, drops to one knee and points to the crowd before breaking into a big smile.
10:39 p.m.: He says he can just now hear the crowds on the Canadian side waiting for his arrival. Before now, all sounds were drowned out by the roaring Falls.
10:38 p.m.: Nik reminds everyone that it's not just mental, it's physical. His hands are just about numb and he's physically drained.
10:37 p.m.: Nik's answering a few more questions and he says the hardest thing was the thick mist and swirling wind. He says that not being able to see was the hardest thing. The swirling wind "was definitely quite a challenge."
10:37 p.m.: Yes, Nik has his passport on him to get into Canada.
10:36 p.m.: 19 minutes, 55 seconds in, Nik crosses the border into Canada. He's about 60 percent of the way done the walk.
10:34 p.m.: Nik asks if his family is over on the Canadian side as he begins to ascend up the wire to dry land.
10:33 p.m.: Nik's dad asks, "How's the harness?" He responds, "It feels fine. I just feel like a jackass wearing it."
10:32 p.m.: Nik's best friend, who hates heights, is up there holding on to the wire.
10:32 p.m.: Nik's daughter wanted him to wear her Hello, Kitty sunglasses as a good luck charm. He told her,"Honey, it's a night. I don't need them."
10:31 p.m.: Josh Elliott: "This is a man of singular mental fortitude."
10:30 p.m.: He's been on the wire for 14 minutes now.
10:28 p.m.: Nik: "The only thing that I'm not happy about is that pendulum that we hung the weather station on, it's catching a little more wind." Nik's dad: "You'll get past it soon."
10:27 p.m.: Nik's dad: "Can you hear me OK over the roar of the falls?"
10:27 p.m.: Hannah Storm: "You can see the water dripping off the wire."
10:26 p.m. : Nik is wearing homemade shoes that were made by his mother. "It means so much to me to have a piece of my family along side with me … It's so great to have a family to support me, even when I have crazy ideas like this."
10:24 p.m.: Josh Elliott asks Nik what he sees: "I am so blessed … This is truly breathtaking."
10:22 p.m.: Nik says the harness fine and there are no insects bothering him.
10:20 p.m.: Nik begins his descent down the wire. He has said this is the most difficult part of the walk.
10:19 p.m.: Nik's dad: "How you doing Nik? Think you can answer a question or two?" Nik: "Yeah, sure."
10:18 p.m.: Nik's dad: "You're looking good. Just remember to change the rhythm of your step just a little."
10:17 p.m.: Nik's dad tells him: "You're looking good. You need to relax a little."
10:16 p.m.: He's off!
10:16 p.m.: Nik's dad Terry, who's inside our production truck, will have the only contact with Nik while he's on the wire.
10:11 p.m.: Just minutes away!
10:08 p.m.: The Wallenda family prays together moments before he gets on the wire. Now they're hustling to the Canadian side of the Falls so they can be there at the end of his walk.
10:05 p.m.: Josh Elliott: "Suddenly, more by the second, this starts to feel impossible."
10:04 p.m.: Sam Champion says that this is the thickest pocket of water they've seen over the Falls over the past two days and he's worried Nik won't be able to see very far.
10:03 p.m.: Bill Weir: "I can't get over how calm, cool and collected this cat is on this wire." And we've gotten the OK from the safety inspector.
10:02 p.m.: Just over 10 minutes away!
10:01 p.m.: Hannah Storm asks Josh Elliott: "Are you nervous?"
10:00 p.m.: Nik Wallenda: "People say I'm insane all the time, but I love what I do."
9:54 p.m.: Nik Wallenda heads to the lift to go up to the wire.
9:53 p.m.: Josh Elliott asks Nik about the falls and he says, "It looks good and it looks exciting and I'm always up for a new challenge."
9:51 p.m.: Never in the history of his career has Nik worn a safety tether. He says he doesn't feel like he has the freedom that he's used to, but he "respects his partners" and "it is what it is."
9:51 p.m.: Nik Wallenda's interview before he walks. He's "extremely excited" and considers himself "so blessed."
9:50 p.m.: 21 minutes left to go! We're almost there.
9:44 p.m.: Bill Weir is with some of the tens of thousands of people who have turned out to watch Nik's historic attempt.
9:39 p.m.: Nik Wallenda is preparing for his walk and putting his harness on. Learn more about the safety precautions here.
9:38 p.m.: The wind is picking up. According to Sam Champion's weather infographic, it's now a 9 MPH.
9:36 p.m.: It's a weird weather pattern tonight which could make Nik's walk harder. Yikes. According to Sam Champion, the hardest thing is the swirling wind pattern. Nik will actually be able to see this as he walks over the falls.
9:29 p.m.: The heel is the part of the foot most sensitive to vibration. And one of Nik's biggest challenge is that humans are top heavy. Who knew?
9:28 p.m.: Less than 45 minutes to go!
9:21 p.m.: Bill Weir touches the wire says, "It gives you the heebie jeebies feeling this thing move like a living creature in your hands right there. Right there is the path Nik will take." Check out this pic of his path.
9:20 p.m.: @JoshElliottABC Yes…no one sneaks in…. RT @olympicfan68 Josh, will a Canadian customs official meet him when he gets off the wire on the Canadian side?
9:18 p.m.: Nik's wife says, "We are normal people. We just have really dangerous jobs."
9:17 p.m.: Nik was raised on the wire. Check out his family history here.
9:15 p.m.: Bill Weir admits to Hannah Storm that he "loves being up here."
9:08 p.m.: Even Robin Roberts is watching the show. @RobinRoberts tweets: Watching my @GMA bros, @SamChampion & @JoshElliottABC..about an hour until @NikWallenda #WalkTheWire..I'm already holding my breath!
9:05 p.m.: Woah. Josh Elliott mentions that at Horshoe Falls where Wallenda will walk there are more than 700,000 gallons of water falling 200 feet down at upwards of 70 mph.
9:03 p.m.: Sam Champion is (wet and) monitoring the weather conditions over the Falls. "It is wet. It is windy and we're not even there yet." As of right now, the temperature is 67 degrees, humidity is 87% and winds are 4 MPH but can gust up to 19 MPH. Get the latest weather conditions at the Falls here.
9:02 p.m. EST: Bill Weir is live on the U.S. side where Wallenda will start his walk. He recalls a famous line from Nik Wallenda's great grandfather, Karl: "Life is on the wire. Everything else is just waiting." Nik has waited 27 years for this opportunity and we're just over an hour away.
9 p.m.EST: There's just a little over an hour left till Nik Wallenda starts his historic walk across Niagara Falls. And we're live with the countdown! Josh Elliot and Hannah Storm are live on the Canadian side of the Falls where Wallenda will finish his walk.