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 costumed fan attends Comic-Con International 2014 – Day 1 on July 24, 2014 in San Diego, Calif. (Photo by Joe Scarnici/FilmMagic/Getty Images)

A model poses in front of the new Lamborghini Huracan during the media day of the 84th Geneva International Motor Show, Switzerland, Tuesday, March 4, 2014. (Photo by Laurent Cipriani/AP Photo)

A woman sits with a Great Dane during the first day of the Crufts dog show in Birmingham, central England March 6, 2014. (Photo by Darren Staples/Reuters)

Two men fight in San Jose, Costa Rica, during the Women's Day on March 8, 2014. (Photo by Jeffrey Arguedas/EFE/SIPA Press)

A Sri Lankan leopard is pictured at a zoo in Dehiwala near Colombo on March 3, 2016, on World Wildlife Day. (Photo by Ishara S. Kodikara/AFP Photo)

Women take part in a rally called “March of Whores” to protest against discrimination and violence against women on International Women's Day in Bogota, Colombia, March 8, 2016. (Photo by John Vizcaino/Reuters)