Nik Wallenda to tightrope walk across Grand Canyon on Sunday

When Nik Wallenda traversed Niagara Falls on a tightrope nearly 200 feet above the ground last year, he wasn’t terrified of the height, he was terrified of the tether dragging behind him.

“It freaked me out like you wouldn’t believe,” Wallenda says, “It was like learning to drive on the left side of the road, and then being thrown into New York City.”

Wallenda is famous for his outrageous stunts and usually performs them without a harness -- one could call it the tightrope equivalent of the climbing term “free-soloing.”

Now, he’s back a year later with an even loftier goal: walking across the Grand Canyon.

PHOTOS: Nik Wallenda crosses Niagara Falls

And he’ll be crossing the national landmark at 1,500 feet above the canyon floor – about 1,300 higher than his Niagara Falls walk.

“It only mentally makes a difference, physically it feels about the same,” says Wallenda.

Wallenda, a seasoned professional, has been walking on tightropes since he was 2 years old. He’s a seventh-generation member of the Flying Wallendas family, a circus clan.

He is always looking for new challenges, and inspiration for these settings is often drawn from trips he took in his childhood.

“As I toured with my parents [who were circus performers], they would bring us to tourist destinations. I first saw Niagara Falls when I was 4 or 5, and the Grand Canyon when I was a teenager.”

Wallenda is about to see the latter from an angle few have -- and one with potentially fatal consequences. If he perished mid-performance, he wouldn’t be the first in his family to do so.

His great-grandfather, Karl Wallenda, died in Puerto Rico in 1978 at the age of 73, while walking between two towers of a 10-story hotel.

“I don’t even really consider myself a daredevil because I don’t think that way,” says Wallenda.

A great deal of training and preparation goes into the performance, says Wallenda. He trains with high wind simulators and slippery wires, and practices visualization techniques.

”Honestly, I rarely get a buzz out of what I do,” he says. Though labeled a “thrill seeker,” to him it’s all entirely normal; walking over the edge of Niagara Falls was the first time in a couple years that he felt the familiar “buzz.”

The Discovery Channel will air the feat on Sunday at 8 p.m. EDT / 5 p.m. PDT.

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Twitter: @celinecwright

celine.wright@latimes.com