Kathleen Darling, wife of disabled veteran Caleb Darling, celebrates a shot during a sled hockey game on March 29, 2012 in Aspen, Colorado. (Photo by John Moore/Getty Images)

An F/A-18 Hornet assigned to Strike Fighter Squadron One Five One (VFA-151) emerges from a cloud created when it broke the sound barrier in the skies over the Pacific Ocean, July 7, 1999. (Photo by John Gay/US Navy)

Newly commissioned 2nd lieutenants throw their caps in the air as a team of F-16 Air Force Thunderbirds fly over the 2011 graduating class of the U.S. Air Force Academy on May 25, 2011 in Colorado Springs, Colorado. A total of 1,021 graduates received their diplomas in front of their families and dignitaries at the Academy's Falcon Stadium. (Photo by John Moore/Getty Images)

Weakened by sickness and malnutrition, Arbty Mohammad, 2, lies in the Banadir Hospital on August 12, 2011 in Mogadishu, Somalia. Some 100,000 Somalis have flooded into Mogadishu from drought and famine stricken areas of the country. The UN warned Friday that a cholera epidemic could spread through Mogadishu, as Somalis fill unsanitary makeshift camps throughout the capital. (Photo by John Moore/Getty Images)

“Daredevil Nik Wallenda became the first person to walk on a tightrope across the Niagara Falls, taking steady, measured steps June 15, 2012 for 1,800 feet across the mist-fogged brink of the roaring falls separating the U.S. and Canada”. (Photo by John Moore/David Duprey/AP Photo)

People line the streets as a dragon passes by during the Chinese New Year parade on January 29, 2012 in New York City. Thousands of people turned out to see the event which celebrated the Year of the Dragon. (Photo by John Moore/Getty Images)

Two young women pose for a portrait, dressed in robes after collecting their Bachelor degrees in Conakry on October 12, 2020. Presidential elections are to be held on October 18, with incumbent President bidding for a third term in office, defying critics who say he forced through a new constitution this year enabling him to sidestep two-term presidential limits. (Photo by John Wessels/AFP Photo)

A Fulani Pastoralist carries two baby sheep on her donkey cart as her family move on northwards in Barkedji, Senegal on July 21, 2020. Thousands of Pastoralist families will start the movement north in the next weeks. With the first rains comes fresh grass and water for the Fulani herders' livestock, it also marks the point where most of the Pastoralist will move northwards until the dry season. (Photo by John Wessels/AFP Photo)