Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A person poses on the track during a fashion competition at the Durban July horse racing event in Durban, South Africa, July 2, 2016. (Photo by Rogan Ward/Reuters)

A Dancer, dressed with the traditional Yi costume, waits to perform at the Torch Festival, in Xichang, China's Sichuan province on July 27, 2016. As a result of fast urbanisation in the rural area of China Like Lienchang prefecture, the traditional costume is fading away for the Yi people in daily life. (Photo by Fred Dufour/AFP Photo)

Kristina Elekes, 23, races on her ski during the Bikini Race contest held at Arena Platos Paltinis winter resort, near Sibiu city, 275 Km north from Bucharest, Romania, 06 March 2016. Bikini Race is a timed show on the slopes, at the fourth edition, for women dressed only in swimmsuits and some winter accessories. (Photo by Mihaela Bobar/EPA)

Topless activist Kaila J. walks through the rain following a “Free the Nipple” demonstration in Hampton Beach, New Hampshire August 23, 2015. (Photo by Brian Snyder/Reuters)

An explosion at a petrochemical plant is seen in Rizhao, Shandong province, July 16, 2015. According to Xinhua News Agency, a fire broke out after the explosion, which was caused by a liquified hydrocarbon leak at the plant, on Thursday morning. There was no report of casualties yet. (Photo by Reuters/China Daily)

A man passes by an unfinished street art graffiti made in a stairway by French street artists Zag and Sia in Paris on March 1, 2016. The two artists drew inspiration from famous “Liberty Leading the People” (La Liberte guidant le peuple) painting by French Eugene Delacroix commemorating the July Revolution of 1830 and viewed as a symbol of the French Republic. (Photo by Joel Saget/AFP Photo)

A female goalkeeper saves the ball at the Mathare Environmental Conservation Youth Center during a soccer match to celebrate the International Women's day in Nairobi, Kenya, March 8, 2017. (Photo by Thomas Mukoya/Reuters)