SARASOTA, Fla. » Nik Wallenda, the Florida-based daredevil, acrobat and heir to the famed Flying Wallendas circus family, is afraid of only one thing.

"I would say the only thing I fear is God," said the 34-year-old Wallenda.

He certainly had no fear of walking across Niagara Falls on a tightrope, riding a bike on a high wire 260 feet above the ground or hanging from a hovering helicopter by his teeth.

On Sunday, Wallenda will attempt an even more ambitious feat, even for a man who was born into a family of risk-takers.

He will bid to walk on a tightrope stretched across the Little Colorado River Gorge near the Grand Canyon. The event, which will be broadcast on live television at 8 p.m. EDT on Sunday with a 10 second delay, will take place on the Navajo reservation near Cameron, outside the boundaries of Grand Canyon National Park.

Wallenda will walk a third of a mile across a wire suspended 1,500 feet above the river. (In comparison, the Empire State Building in New York City is 1,454 feet high).

"I respect deeply what I do and realize there’s a lot of danger in it," he acknowledged on a recent day in his Florida hometown of Sarasota.

Wallenda, who is married and has three children, always says a prayer with his family prior to stepping onto the wire.

The 34-year-old is a seventh-generation high-wire artist and is part of the famous "Flying Wallendas" circus family — a clan that is no stranger to death-defying feats and great tragedy.

His great-grandfather, Karl Wallenda, fell during a performance in Puerto Rico and died at the age of 73. Several other family members, including a cousin and an uncle, have perished while performing wire walking stunts.

Nik Wallenda, who was born a year after his great-grandfather died, began wire walking at the age of 2, on a 2-foot high stretched rope. He grew up performing with his family and as a teen, had an epiphany.

"It’s an honor to be carrying on a tradition that my family started over 200 years ago," Wallenda said during a news conference on a recent day in Florida. "When I turned 19, I told my family I was going to set out to make sure everyone in the world knew who the Wallendas were again."

Over the years, Wallenda has performed some dangerous stunts, but his walk across Niagara Falls in June of 2012 placed him firmly in celebrity territory.

Wallenda became the first person to walk on a tightrope 1,800 feet across the mist-fogged brink of the roaring falls separating the U.S. and Canada.

Other daredevils had wire-walked over the Niagara River but farther downstream and not since 1896.

Niagara Falls, Wallenda said, was a dream of his. So is the Grand Canyon.

But here’s the difference between the two stunts: ABC televised the walk and insisted Wallenda use a tether to keep him from falling in the river. Wallenda said he agreed because he wasn’t willing to lose the chance to perform the walk.

On Sunday, the Discovery Channel will televise the walk, but Wallenda won’t wear a tether. There won’t be a safety net, either.

He anticipates it will take him about 30 minutes to cross the chasm.

For the last two weeks, Wallenda — who has a boyish face, strawberry blonde hair and a muscular build — has been practicing in front of crowds in his hometown of Sarasota.

Each morning and evening, he glides across a two-inch cable strung on the banks of a river. Hundreds of his local fans show up every day to watch, and talk — Wallenda usually will stop and sit on the wire and take questions from his fans from high above.

"I’m just fascinated by the movement, the way he walks," said Loy Barker, a Sarasota resident who watched one of Wallenda’s practice sessions. "He’s just an amazing athlete."

Wallenda has tried to simulate different conditions he might face while crossing the gorge.

"It’s very important that I train on a cable that simulates the weight, the feeling, the movement of the cable, the way it will move under my feet," he said. "We have also brought wind machines out. I’ve walked in 52 mile an hour gusts during Tropical Storm Andrea, with a torrential downpour. And we also brought out wind machines where we simulated 45-55 mile per hour gusts. Then I also walked in 91-mile an hour winds that day."

Only one thing could halt the planned wire walk, he says: lightning detected within a 15-mile radius of the wire.

In the meantime, he’s training physically and mentally. Wallenda said the adrenaline has "kicked in" and that he’s anxious to be suspended with only a 2-inch-cable below his feet.

"I absolutely will look down," he said. "And I’ll enjoy the view."

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