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 supercell thunderstorm develops, May 8, 2017 in Elbert County outside of Limon, Colorado. With funding from the National Science Foundation and other government grants, scientists and meteorologists from the Center for Severe Weather Research try to get close to supercell storms and tornadoes trying to better understand tornado structure and strength, how low-level winds affect and damage buildings, and to learn more about tornado formation and prediction. (Photo by Drew Angerer/Getty Images)

Meropidae are seen on a rock in Van in Turkey on March 03, 2018. (Photo by Ali Ihsan Ozturk/Anadolu Agency/Getty Images)

A boy covers his head with fallen leaves as he enjoys a stroll with his family in a park in downtown Frankfurt, Germany, November 6, 2016. (Photo by Kai Pfaffenbach/Reuters)

Winter swimmers dressed in ballet costumes pose for a photo before diving into the icy water, during a snowfall at a park in Shenyang, Liaoning province, China on February 15, 2019. (Photo by Reuters/China Stringer Network)

Model Irina Shayk wears a creation as part of the Versace men's Spring-Summer 2020 collection, unveiled during the fashion week, in Milan, Italy, Saturday, June 15, 2019. (Photo by Luca Bruno/AP Photo)

Riot police detain a woman during a protest near Mong Kok police station in Hong Kong, China on September 7, 2019. (Photo by Tyrone Siu/Reuters)

A view shows a church in front of a high-rise apartment building in Saint Petersburg, Russia on October 30, 2019. (Photo by Anton Vaganov/Reuters)