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

The setting sun illuminates the sky behind wind turbines of a wind park near Neusiedl am See, December 22, 2014. (Photo by Heinz-Peter Bader/Reuters)

A man walks through the morning mist in a park in Rozzano, near Milan, northern Italy, Thursday, December 17, 2015. (Photo by Antonio Calanni/AP Photo)

The northern lights, or aurora borealis, illuminate the sky over Flakstad beach on Lofoten Islands in the Arctic Circle on September 5, 2017. (Photo by Jonathan Nackstrand/AFP Photo)

An Exmoor wild goat silhouetted in the sky over the Bristol Channel at the valley of the Rocks, North Devon, as the UK's heat wave continues on July 19, 2018. (Photo by Paul Silver/South West News Service)

A man selling bags of water is seen at a taxi parking bay lined with campaign posters in the district of Lingwala in Kinshasa on December 18, 2018. Democratic Republic of Congo goes to the polls on December 23, 2018 in elections which could see the country emerge from 17 years of conflict-ridden rule under controversial President Joseph Kabila. (Photo by John Wessels/AFP Photo)

A seagull eats a piece of dried fish of a man's hand during sunset at Bang Pu seaside resort in Samut Prakan province on the outskirts of Bangkok, Thailand, 13 January 2019. Every year during the cold winter months between October to March thousands of seagulls migrate to Bang Pu seaside from Siberia to escape the harsh winter. (Photo by Diego Azubel/EPA/EFE)

Young Turkana tribeswomen sing in a village near Baragoy, Kenya August 6, 2017. Kenyans are due to go to the polls on Aug. 8. to vote in presidential elections after a tightly-fought race between President Uhuru Kenyatta and main opposition leader Raila Odinga. (Photo by Goran Tomasevic/Reuters)