A member of the Eton public school O.T.C. (Officers Training Corps) practising shouting out orders during a training session, 20th January 1940. (Photo by Hulton Archive/Getty Images)

Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

People wait for a subway train to depart Union Square station, in New York City on June 1, 2025. (Photo by Kevin Coombs/Reuters)

New York City, 1974. (Photo by Elliott Erwitt/Harry Ransom Center Collection/Magnum Photos)

A reveller takes part in the Holi Party Festival at Niemeyer Center in Aviles, northern Spain, August 27, 2016. (Photo by Eloy Alonso/Reuters)

Singer Rihanna in the audience at the 54th Annual GRAMMY Awards held at Staples Center on February 12, 2012 in Los Angeles, California. (Photo by Larry Busacca/Getty Images For The Recording Academy)

Pro-Russian separatists from the Chechen “Death” battalion take part in a training exercise in the territory controlled by the self-proclaimed Donetsk People's Republic, eastern Ukraine, December 8, 2014. Chanting “Allahu Akbar” (God is greatest), dozens of armed men in camouflage uniforms from Russia's republic of Chechnya train in snow in a camp in the rebel-held east Ukraine. They say their “Death” unit fighting Ukrainian forces has 300 people, mostly former state security troops in the mainly-Muslim region where Moscow waged two wars against Islamic insurgents and which is now run by a Kremlin-backed strongman. (Photo by Maxim Shemetov/Reuters)