A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)

A visitor is reflected in a light installation at Mulberry Lights on Regent Street in London, UK on November 16, 2018. Visitors have fun taking selfies and posing with the colourful light installations. Mulberry Lights is a series of illuminating interactive experiences that celebrate how light, colour, shapes and people come together to create a modern British Christmas. (Photo by Imageplotter/Rex Features/Shutterstock)

The Aurora Borealis (Northern Lights) is seen over the sky near Inari in Lapland, Finland on February 14, 2019. (Photo by Alexander Kuznetsov/Reuters)

A girl walks an Akita-inu dog dressed in a military uniform in Vladivostok, Russia on April 9, 2019. (Photo by Yuri Smityuk/TASS)

A woman throws water at passing motorists during celebrations for the Thingyan festival, also known as the Buddhist New Year, in Naypyidaw, Myanmar on April 16, 2019. (Photo by Thet Aung/AFP Photo)

Fans dressed up in costume await the cast members on the red carpet at the world premiere of the film "The Avengers: Endgame" in Los Angeles, California, April 22, 2019. (Photo by Mario Anzuoni/Reuters)

Moruti Mthalane of South Africa is punched by Masayuki Kuroda of Japan during their IBF flyweight title boxing bout in Tokyo on May 13, 2019. (Photo by Charly Triballeau/AFP Photo)

Dancers are warming up backstage during the Tango Dancing Tournament at the XIII International Tango Festival in Medellin, Colombia, on June 18, 2019. The Tango Festival takes place between the 16th and 24th of June. (Photo by Joaquin Sarmiento/AFP Photo)