From the Toronto Star:
Wallenda can’t afford to make a similar stumble this Friday during his highest-profile act yet: walking 550 metres across Niagara Falls, on a wire 60 metres above the gorge.
“This is unique because it’s the longest unsupported or unstabilized cable that anyone’s put up in the history of wire-walking,” Wallenda says.
And if the much-publicized stunt is a success, he’ll also be the first person to cross right over the falls.
A number of daredevils have walked across the gorge further downstream, but no one has gone directly above the falls themselves. It has been more than 100 years since anyone has even attempted a crossing.