Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A 20 metre high spiral staircase in a tower used as an emergency exit, is seen inside a Federal Reserve bank (Bundesbank) bunker, prior to the bunker's official opening to the public in Cochem, Germany, March 18, 2016. West Germany's Central Bank (Deutsche Bundesbank) stored some 20 billion German marks of emergency notes in two underground bunkers, one in Frankfurt the other in Cochem, between 1964-1988 during the cold war. (Photo by Kai Pfaffenbach/Reuters)

A Pakistani vendor tries to salvage materials after flood water destroyed his shop following heavy rain on the outskirts of Peshawar on April 4, 2016. (Photo by A. Majeed/AFP Photo)

A woman washes her dishes outside the temporary shelter built near the houses damaged during an earthquake earlier this year, in Bhaktapur, Nepal December 28, 2015. (Photo by Navesh Chitrakar/Reuters)

A resident removes mud on a street brought by monsoon rains in San Mateo, Rizal, Philippines, August 14, 2016. (Photo by Erik De Castro/Reuters)

A South Korean marine in action during their regular drill on Yeonpyeong Island, South Korea November 1, 2018. (Photo by Jeon Heon-Kyun/Pool via Reuters)

Argentinian dancer Maria Belen Ciaschi, stranded in Lebanon due to COVID-19 coronavirus pandemic, dances flamenco to the music played by Uruguayan singer Walter Javier Maulelo while both wearing a mask on a seafront boardwalk in the northern coastal city of Batroun, on April 15, 2020. (Photo by Ibrahim Chalhoub/AFP Photo)