Tiffany Porter of Britain falls after competing in the women's 100 metres hurdles final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 28, 2015. (Photo by David Gray/Reuters)

A Tampa Bay Buccaneers cheerleader, wear a military-inspired outfit as part of the NFL's Salute to Service program, flips her hair during a game between the Buccaneers and San Diego Chargers in Tampa, on November 11, 2012. (Photo by Phelan M. Ebenhack/Associated Press)

Sydneysiders take part in the “AIME Strut the Streets” in an attempt to break the Guiness record for the world's largest swimwear parade on December 7, 2012 in Sydney, Australia. The event was organised to raise funds and awareness for the not for profit charity organisation, the Australian Indigenous Mentoring Experience. (Photo by Lisa Maree Williams)

Leidi, a member of the 51st Front of the Revolutionary Armed Forces of Colombia (FARC), poses for a picture at a camp in Cordillera Oriental, Colombia, August 16, 2016. A peace deal will end half a century of war and allow the rebels to reintegrate into Colombian society. (Photo by John Vizcaino/Reuters)

Mark Dill and Brit Thacker practice acro-yoga as approximately 70,000 people from all over the world gather for the 30th annual Burning Man arts and music festival in the Black Rock Desert of Nevada, U.S. August 29, 2016. (Photo by Jim Urquhart/Reuters)

An armed youth loyal to the Houthi movement takes part in a protest against the Saudi-backed exiled government deciding to cut off the Yemeni central bank from the outside world, in the capital Sanaa, Yemen August 25, 2016. (Photo by Mohamed al-Sayaghi/Reuters)

Employee of ornithological flight support service Nika Ryzhova-Alenicheva holds her hawk, which is used to control fauna to avoid bird strikes during takeoffs and landings, at Domodedovo airport outside Moscow, Russia September 2, 2016. (Photo by Maxim Zmeyev/Reuters)

A pilgrim prays at Mount Al-Noor, where Muslims believe Prophet Mohammad received the first words of the Koran through Gabriel in the Hera cave, ahead of the annual haj pilgrimage in the holy city of Mecca, Saudi Arabia September 7, 2016. (Photo by Ahmed Jadallah/Reuters)