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 US soccer fan cheers during the FIFA World Cup 2014 group A preliminary round match between Brazil and Croatia at the FIFA Fan Fest in Copacabana, Rio de Janeiro, Brazil, 12 June 2014. Brazil won 3-1. The FIFA World Cup 2014 will take place in Brazil from 12 June to 13 July 2014. (Photo by Abedin Taherkenareh/EPA)

Beloni (34) gives a bath to his son, 6, on a small street in the neighborhood of Cite Vincent, on March 21, 2016 in the commune of Cite Soleil in the Haitian capital Port-au-Prince. World Water Day, marked on March 22, 2016, is an international observance to learn more about water related issues and to take action for sustainable management of freshwater resources. (Photo by Hector Retamal/AFP Photo)

A man from the Dominican Republic wears a devil mask while dancing in the street during Carnival celebrations in Panama City, Monday, February 16, 2015. (Photo by Arnulfo Franco/AP Photo)

Valentin Arias Delgado and Diana Franco Durango, from Colombia, perform their routine at the Stage style Tango World Championship, in Buenos Aires, Argentina, August 31, 2016. (Photo by Enrique Marcarian/Reuters)

A participant from Indonesia waits to perform a dance during the last day of World Culture Festival on the banks of the river Yamuna in New Delhi, India, March 13, 2016. The festival opened on the banks of the Yamuna River in the Indian capital Friday despite concerns the sprawling construction of roads, ramps and pontoon bridges would irreparably damage the river's floodplains. (Photo by Adnan Abidi/Reuters)

Genzebe Dibaba of Ethiopia competes in the women's 1500m semi-final during the 15th IAAF World Championships at the National Stadium in Beijing, China August 23, 2015. (Photo by Lucy Nicholson/Reuters)

A Palestinian protester, dressed as Santa Claus, reacts after inhaling tear gas fired by Israeli troops during clashes in the West Bank city of Bethlehem December 23, 2016. (Photo by Mussa Qawasma/Reuters)