A wide-angle view shows the ascent of the shuttle Challenger on January 28, 1986. In the seconds after ignition, the rocket engines' hot blast began the process of destruction. (Photo by NASA)
A competitor poses before the Tough Guy Challenge endurance race on January 27, 2013 in Telford, England. Every year thousands of people run the 8 mile assault course which involves freezing temperatures, fire and ice. (Photo by Michael Regan)
A competitor in fancy dress emerges from muddy water during the Tough Guy Challenge endurance race on January 29, 2012 in Telford, England. Every year thousands of people run the 8 mile assault course which involves freezing temperatures, fire and ice. (Photo by Michael Regan/Getty Images)
Participants run through the flames in the 2011 Spartacus Challenge on October 2, 2011 in Wolverhamton, England. (Photo by Dean Mouhtaropoulos/Getty Images)
“Freestyle skiing is an acrobatic form of technical and aerial skiing. It is organized into a number of different disciplines”. – Wikipedia
Photo: Freeskier Chris Booth of Australia launches off a drop during the World Heli Challenge freestyle day in backcountry at Minaret Station on July 31, 2011 in Wanaka, New Zealand. (Photo by Cameron Spencer/Getty Images)
An Egyptian university student drives a hybrid racing car he built with his team to compete at the Global Hybrid-Electric Challenge in Cairo, Egypt September 2, 2016. (Photo by Mohamed Abd El Ghany/Reuters)
A runner traverses the route during the Mount Everest Challenge Marathon which winds past spectacular views of Everest and Kanchenjunga at Sandakphu National Park in the month of November 1995 near Darjeeling, India.
An Estonian competitor cheers during the “World Medieval Fighting Championship – the Israeli Challenge” in Rishon Letzion near Tel Aviv January 22, 2015. Israel hosted the tournament on Thursday, which includes 14 competitors from seven different countries – France, Belarus, Denmark, Estonia, Russia, Ukraine and Israel. (Photo by Amir Cohen/Reuters)