Combat between two male stag beetles, Italy, 2022. During the mating season, male stag beetles (Lucanus cervus) go into a frenzy, with lively but harmless clashes, in which bigger males often have the advantage over smaller ones due to their impressive mandibles. Longer larval development and genetic traits can increase the size of some individuals, but all saproxylic beetles are threatened by poor forest management, logging and dead wood removal to “clean” the forest. (Photo by Iacopo Nerozzi)

A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925

Syrian refugee and Olympic swimmer Yusra Mardini is pictured during a training session in a pool at the Olympic park in Berlin, Germany on April 26, 2018. (Photo by Fabrizio Bensch/Reuters)

Bob Steele, of Jefferson, Texas, positions his bears during The Great Bear Show at the Dubuque (Iowa) County Fair on July 25, 2012. (Photo by Jessica Reilly/Telegraph Herald)

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

A giant size figure of the United States' goalkeeper Tim Howard is displayed outside a shopping mall in Hong Kong, Thursday, June 12, 2014, to promote the upcoming 2014 World Cup in Brazil. A total of seven 3.5 meters to 4 meters (11 feet 6 inch to 13 feet one inch) tall figures of famous players attract many soccer fans. (Photo by Vincent Yu/AP Photo)

Some of London's telephone operators and engineers, trying out their gas masks at the anti-gas civilian training centre in Gloucester, where they were taught how to deal with gas attacks. (Photo by Harry Todd/Fox Photos/Getty Images). 13th February 1937

A bulldog named Munch, left, and a puppy named Dominique attend a news conference at the American Kennel Club in New York, Wednesday, January 30, 2013. The club announced their list of the most popular dog breeds in 2012 where the bulldog takes the fifth place spot from the Yorkshire terrier. (Photo by Seth Wenig/AP Photo)