A reveler gets ready to perform at a carnival parade in Havana, Cuba August 7, 2015. (Photo by Alexandre Meneghini/Reuters)

A man wearing a floral arrangement on his back takes part in the annual flower parade, in which flower growers known as “silleteros” present their floral arrangements, in Medellin, Colombia, August 9, 2015. (Photo by Fredy Builes/Reuters)

Revellers take part in the 21st Rio LGBT pride parade at Copacabana beach in Rio de Janeiro, Brazil, on December 11, 2016. (Photo by Yasuyoshi Chiba/AFP Photo)

Željava Air Base, situated on the border between Croatia and Bosnia and Herzegovina under Plješevica Mountain, near the city of Bihać, Bosnia, was the largest underground airport and military air base in the former Yugoslavia, and one of the largest in Europe. (Photo by Thomas Windisch/Exclusivepix Media)

Afghan National Army (ANA) soldiers sit waiting to return their weapons after a day of traning at the Kabul Military Training Center (KMTC) October 3, 2010 in Kabul, Afghanistan. There are between 5,000 to 7,000 troops on the training facility in eight-week cycles trained by the coalition forces to ultimately take over the role of military operations in the country. (Photo by Paula Bronstein/Getty Images)

Participants wearing masks during a hazy day at the Beijing International Marathon in front of Tiananmen Square, in Beijing, October 19, 2014. (Photo by Reuters/Stringer)

Emma Coburn (L) and Colleen Quigley of the U.S. look at the scoreboard after competing in the women's 3,000 metres steeplechase final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 26, 2015. (Photo by David Gray/Reuters)