The holder of half a dozen world records will walk across the Grand Canyon on a steel cable with nothing but the Little Colorado River 1,500 feet below on June 23. With no tethers or safety nets, the walk will be the highest tightrope attempt ever for the 34-year-old, at a height taller than the Empire State Building. Last year, Wallenda, a seventh-generation member of the “Flying Wallendas” family of acrobats, became the only person to walk a wire over the brink of Niagara Falls. Photo: Nik Wallenda walks across a tightrope 200 feet above U.S. 41 on January 29, 2013 in Sarasota, Florida. (Photo by Tim Boyles)

A man walks beside a “Wrinkles Of The City” creation near the Berlin cathedral in Berlin April 19, 2013. (Photo by Fabrizio Bensch/Reuters)

A reveller smiles as she walks in the rain at Worthy Farm in Somerset during the Glastonbury Festival in Britain, June 28, 2015. (Photo by Dylan Martinez/Reuters)

Women in Kimono holding an umbrella walk on a street at Ginza shopping district in Tokyo, Japan, March 31, 2016. (Photo by Yuya Shino/Reuters)

An Afghan woman walks along a street covered with snow on the outskirts of Kabul, Afghanistan February 7, 2017. (Photo by Omar Sobhani/Reuters)

Two girls in cosplay dresses walk in the street in Beijing on March 27, 2017. (Photo by Fred Dufour/AFP Photo)

Model Ashley Graham is seen walking in Soho on May 9, 2017 in New York City. (Photo by Raymond Hall/GC Images)

A man carrying a sailfish walks through Hamarweyne district in South Mogadishu on March 25, 2015. (Photo by Carl De Souza/AFP Photo)