A U.S. Marine leads training on a shooting range in France in an undated photo taken during the First World War. (Photo by Reuters/Courtesy Library of Congress)

Paramilitary policemen take part in a summer training in Shenzhen, Guangdong province, China, June 27, 2016. (Photo by Reuters/China Daily)

Paramilitary policemen take part in a training in Chaohu, Anhui province, China December 28, 2015. (Photo by Reuters/China Daily)

A man sleeps in a subway train in New York city on August 1, 2024. (Photo by Charly Triballeau/AFP Photo)

A woman dressed up for Halloween travels on a Metro train in São Paulo, Brazil on October 30, 2017. (Photo by Cris Faga/Rex Features/Shutterstock)

Passengers travel in an overcrowded train in the eastern Indian city of Patna, February 23, 2010. (Photo by Krishna Murari Kishan/Reuters)

A subway worker walks away after a train departed the station in central Pyongyang, North Korea May 7, 2016. (Photo by Damir Sagolj/Reuters)

A migrant boy sits on railway tracks at a train station in Tovarnik, Croatia, September 20, 2015. (Photo by Antonio Bronic/Reuters)