A Chesterfield Borough Police telephone operator tests a gasmask with built in earpiece and microphone. The telephone service is considered one of the most important links in the coordination of ARP operations and must remain operational during air raids, 12th April 1939. (Photo by Fox Photos/Hulton Archive/Getty Images)

Pigeons cool down at a public fountain on a hot summer day at University Plaza in downtown Bucharest, Romania, 10 June 2020. Temperatures in Bucharest reached 30 degrees Celsius. (Photo by Robert Ghement/EPA/EFE)

Girls of University of Cincinnati Stage Grecian Games on April 29, 1921. Garbed in costumes of ancient Greece, fair students of the University of Cincinnati, Ohio arranged a set of Grecian Games for the benefit of the University athletic fund. All of the girl students of the University, who take a great interest in outdoor games and athletics, took part in the games. The fund was greatly increased through the staging of the unique attraction and the girls purpose to give a return engagement. The accompanying photographs show the girl contestants in their Grecian costumes. Photo shows the start of the 100 yard dash. (Photo by Bettmann Archive/Getty Images)

People stand and take selfies in front of lava from the eruption of Mount Nyiragongo, in Buhene, on the outskirts of Goma, Congo in the early hours of Sunday, May 23, 2021. Congo's Mount Nyiragongo erupted for the first time in nearly two decades Saturday, turning the night sky a fiery red and sending lava onto a major highway as panicked residents tried to flee Goma, a city of nearly 2 million. (Photo by Justin Kabumba/AP Photo)

In this Sunday June 13, 1988 file photo West German police officers arrest an English soccer hooligan who sticks out his tongue. Rioting broke out between some 100 hooligans and the police in downtown Stuttgart, West Germany following the European Soccer Championships match between England and Ireland. England was defeated by Ireland 0-1. (Photo by Kraufmann/AP Photo/File)

A man walks his dog through Los Berros Mountain in El Paso with the Cumbre Vieja volcano in the background, on the Canary Island of La Palma, Spain, October 24, 2021. (Photo by Borja Suarez/Reuters)

Photo taken on October 11, 2020 shows a golden monkey at Dalongtan Golden Monkey Research Center in Shennongjia National Park of central China's Hubei Province. With the efforts of local authority and improvement of the environment in the past many years, the number of golden monkeys in Shennongjia area reached nearly 1,500 nowadays. (Photo by Xinhua News Agency/Rex Features/Shutterstock)

A mural depicting NHS nurse Melanie Senior, based on a photograph by Johannah Churchill, which The National Portrait Gallery commissioned artist Peter Barber to create in Manchester's Northern Quarter, on October 19, 2020 in Manchester, England. Greater Manchester's leaders including Mayor Andy Burnham will want better financial arrangements for workers affected before they agree for the region to be moved into a Tier 3 Covid-19 lockdown. (Photo by Christopher Furlong/Getty Images)