Vocalist Laila Skovmand, a musician with Danish company Between Music, plays underwater in a tank during a rehearsal ahead of their UK premiere concert Aquasonic at the Tramway in Glasgow on Ocrober 25, 2017. (Photo by Robert Perry/PA Images)

Soviet Army soldiers sit on their tanks in front of the Czechoslovak Radio station building in central Prague during the first day of Soviet-led invasion to then Czechoslovakia on August 21, 1968. (Photo by Libor Hajsky/Reuters)

A Ukrainian serviceman wearing a new year's hat waves at his comrades while standing beside his tank near Debaltseve, eastern Ukraine, February 8, 2015. (Photo by Gleb Garanich/Reuters)

Pro-government fighters stand next to a tank destroyed during recent fighting in Yemen's southwestern city of Taiz March 14, 2016. (Photo by Anees Mahyoub/Reuters)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

Local people check the growth of mussels at a river in Haian County on November 2, 2017 in Nantong, Jiangsu Province of China. Fish, shrimp, crab and mussel farming cleans the river and increases the villagers' income at Haian county in Jiangsu. (Photo by VCG/VCG via Getty Images)

An Afghan man cleans the his courtyard partially submerged in flood water following the flash floods after heavy rainfall in Guzara district of Herat province on March 13, 2024. (Photo by Mohsen Karimi/AFP Photo)

Passengers check their mobile devices as a bin is full of garbage during a protest by the cleaning staff at Barcelona's airport, Spain, December 1, 2016. (Photo by Albert Gea/Reuters)