U.S. President Donald Trump boards Air Force One to depart for Vietnam from Beijing Airport in Beijing, China on November 10, 2017. (Photo by Jonathan Ernst/Reuters)

A line of soldiers firing handguns during a training session, circa 1920. (Photo by Keystone). P.S. All pictures are presented in high resolution.

A thirty-year-old Dutch demonstrator displays a sign that reads: “Glad to be Gay” during a gay people march in Frankfurt, Germany on Saturday, July 28, 1979 which ended a week long homosexual meeting. Hundreds of homosexual converged for a week of movies, theater, rock concerts and workshops on gay rights. (Photo by Rolf Boehm/AP Photo)

Cars slowly move along a bridge in traffic jam in central Moscow, Russia on December 11, 2018. (Photo by Yuri Kadobnov/AFP Photo)

Youths parade wearing World War Two uniforms during the Independence Day celebrations in Gdansk November 11, 2014. (Photo by Lukasz Glowala/Reuters/Agencja Gazeta)

After finding the bricklaying business too full of ups and downs, this amazing young girl decided to take a shot at iron girdering for a change. She is Miss “Collie” Collier, a reporter for the Chicago Herald-Examiner. August 17, 1920. (Photo by Bettmann Archive/Getty Images)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

A competitor shouts as he takes part in the “Tough Guy” adventure race near Wolverhampton, central England, on January 29, 2017. The Tough Guy event, which is being held for the final time in its 30th year, challenges thousands of competitors to run a gruelling course whilst negotiating over 200 obstacles including: water, fire, and tunnels. (Photo by Oli Scarff/AFP Photo)