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)

The Wadi al-Salam cemetery, Arabic for “Peace Valley”, is seen in Najaf, south of Baghdad, Iraq August 3, 2016. The world's largest cemetery, in Iraq's Shi'ite holy city of Najaf, is expanding at double its usual rate as Shi'ite militias bury their dead from the war against Islamic State. The Wadi al-Salam cemetery, Arabic for “Peace Valley” has a special place in the hearts of Shi'ite Muslims as it surrounds the Mausoleum of their first imam, Ali Bin Abi Talib, a cousin and son-in-law of Prophet Mohammad. (Photo by Alaa Al-Marjani/Reuters)

A dead red-tailed monkey hangs by its tail above the ground, in order to keep it away from ants, in the forest near the city of Mbandaka, Democratic Republic of the Congo, April 5, 2019. Bushmeat hunters are emptying Central Africa's forests at a high rate, researchers say. A growing appetite for wild meat in cities has ramped up the scale of hunting. Research shows around 6 million tonnes of bushmeat are sourced annually from the Congo Basin, whose forest spans across six countries and is second in size only to the Amazon. (Photo by Thomas Nicolon/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)

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

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)

Miss Alsace, Delphine Wespiser walks along the stage during Miss France 2012 Beauty Pageant on December 3, 2011 in Brest, France. (Photo by Pascal Le Segretain/Getty Images)

A model walks down the runway during the Safilo fashion show at the Mercedes-Benz Fashion Pavilion on January 30, 2012 in Stockholm, Sweden. (Photo by Ian Gavan/Getty Images)