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)

Models wait for their turn at an audition for the upcoming Lakme Fashion Week (LFW) Summer/Resort 2017 in Mumbai, India, 14 December 2016. Around 83 national and international models participated in the audition from which five got selected. The LFW Summer/Resort 2017 is scheduled to start from 01 to 05 February 2017. (Photo by Divyakant Solanki/EPA)

A guide dangles a live chicken in front of a crocodile in the village of Bazoule, Burkina Faso, December 4, 2015. The villagers believe the crocodiles that live there are sacred. (Photo by Joe Penney/Reuters)

An athlete dressed as a clown jumps into the Mediterranean sea as he takes part in the Copa Nadal in the Spanish port of Barcelona in Barcelona, Spain, Sunday, December 25, 2016. The Copa Nadal (Christmas Cup) is a traditional swimming competition that takes place in Barcelona every December 25th, where participants swim 200 meters in the open sea in the port of Barcelona. (Photo by Manu Fernandez/AP Photo)

Pakistani civil society activists release lanterns into the sky in Lahore on December 15, 2016, as they pay tribute to victims on the second anniversary of an attack on The Army Public School in the city of Peshawar. Taliban militants attacked on Pakistani Army Public School in Peshawar, killing 151 people mostly children on December 16, 2014. (Photo by Arif Ali/AFP Photo)

People try out the XIM 17 vehicle interior concept unveiled by Yanfeng Automotive Interiors during the North American International Auto Show in Detroit, Michigan, U.S., January 10, 2017. (Photo by Brendan McDermid/Reuters)

Personal trainer, Denise Austin, and Katie Austin arrive at the ESPY Awards at the Microsoft Theater on Wednesday, July 13, 2016, in Los Angeles. (Photo by Jordan Strauss/Invision/AP Photo)

A demonstrator jumps from a vehicle of the Organisation for Security and Co-operation in Europe (OSCE) during a protest to demand what protesters say is true information from the OSCE about the shelling in Donetsk, Ukraine (since April 2014, the city is the administrative centre of the Donetsk People's Republic), July 23, 2015. The graffiti reads, “Stop moronic war!”. (Photo by Alexander Ermochenko/Reuters)