Military vehicles surround a wreckage of a trolleybus, in Volgograd, Russia, Monday, December 30, 2013. A bomb blast tore through a trolleybus in the city of Volgograd on Monday morning, killing at least 10 people a day after a suicide bombing that killed at least 17 at the city's main railway station. Volgograd is about 650 kilometers (400 miles) northeast of Sochi, where the Olympics are to be held. (Photo by Denis Tyrin/AP Photo)

An instructor (C) adjusts the posture of students of flight attendant major during a training session at Anhui Foreign Languages University, in Hefei, Anhui province, China, May 25, 2015. (Photo by Reuters/China Daily)

Members of the U.S. Army's Golden Knights parachute team perform during the Bethpage Air Show as part of a Memorial Day event at Jones Beach on Long Island, New York, U.S., May 25, 2019. (Photo by Johnny Milano/Reuters)

Joseph Fons holding a Pride Flag, runs in front of the U.S. Supreme Court building after the court ruled that a federal law banning workplace discrimination also covers sexual orientation, in Washington, D.C., U.S., June 15, 2020. (Photo by Tom Brenner/Reuters)

In this July 20, 2019 photo, children play during a sports event organized by members of the Caracas FC soccer club, in Catia, one of the poorest slums in Caracas, Venezuela. When the Caracas Football Club plays, its supporters leave their ideological preferences and socioeconomic differences behind, joining together to support and take care of each other inside and outside the stadium. (Photo by Matias Delacroix/AP Photo)

Fascist youth, both boys and girls, in the rebel uniforms in Irun after the city had been captured by the rebels. (Photo by Maeers/Fox Photos/Getty Images). 13th November 1936

A monkey is led by its trainer Qi Defang during training for a circus in Suzhou, Anhui province, November 29, 2014. Suzhou is known as the hometown of circus troupes in China and has more than 300 circus troupes. (Photo by William Hong/Reuters)

A zoo performer smiles as he puts his head between the jaws of a crocodile during a performance for tourists at the Sriracha Tiger Zoo, in Chonburi province, east of Bangkok,Thailand, June 7, 2016. (Photo by Chaiwat Subprasom/Reuters)