Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

Bikini-clad women ski as they are led by a car during a performance on the frozen Yenisei River outside Krasnoyarsk, Siberia, Russia, March 20, 2016. The performance, entitled “Siberian Spring's Strings” and created with the participation of artist Vasily Slonov, marked the day of spring equinox (vernal equinox), according to organizers. (Photo by Ilya Naymushin/Reuters)

Kyrgyz men on horseback compete during their traditional game of “Oodarysh” during the celebrations of the 90th anniversary formation of the Chui region in the village of Kuntu some 20 kms from Bishkek on May 27, 2016. (Photo by Vyacheslav Oseledko/AFP Photo)

A young Thai man jumps in the air and cheers as his rocket takes off at the Bun Bang Fai Rocket Festival on May 10, 2015 in Yasothon, Thailand. During the Bun Bang Fai rocket festival, Thai residents launch enormous home-made rockets into the air to gain Buddhist merit and to celebrate the beginning of the rainy season. (Photo by Taylor Weidman/Getty Images)

Attendees look at Volkswagen's BUDD-e, a long distance electric vehicle, displayed during a press event at CES 2016 at The Chelsea at The Cosmopolitan of Las Vegas on January 5, 2016 in Las Vegas, Nevada. CES, the world's largest annual consumer technology trade show, runs from January 6-9 and is expected to feature 3,600 exhibitors showing off their latest products and services to more than 150,000 attendees. (Photo by David Becker/Getty Images)

A racegoer enjoy the atmosphere following 2016 Derby Day at Flemington Racecourse on October 29, 2016 in Melbourne, Australia. Women attendees weren’t afraid to show off some skin as the warm summer weather arrived in Australia. (Photo by Splash News and Pictures)

Members of the New People's Army (NPA) female guerrillas perform a cultural show during the release of a Philippines army soldier in Sugbongcogon town, Misamis Oriental, southern Philippines, November 20, 2015. NPA spokesperson Allan Juanito warned that they will seize more soldiers to exchange them with the government as "Prisoners of war". (Photo by Froilan Gallardo/Reuters)

Cyclists compete during the UCI BMX World Championships Elite Women's Moto Race on May 29, 2016 in Medellin, Antioquia department, Colombia. (Photo by Raul Arboleda/AFP Photo)