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

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

A child attends a training session in a swimming pool on July 10, 2007 in Wuhan of Hubei Province, China. (Photo by China Photos/Getty Images)

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 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)

An Iraqi army cadet participates in “the leap of faith”, from a bridge as part of their training, in Baghdad, Iraq on December 15, 2023. (Photo by Ahmed Saad/Reuters)

Aeronautics and Space engineer at France's Compagnie Maritime d'Expertises, or Comex, Arnaud Prost (C) meets with a jogger as he tests on the ground the “Gandolfi 2” underwater training suit for spacewalk, on January 20, 2016 in the calanques region (rocky inlets) of Marseille. The underwater training suit “Gandolfi 2”, developed with the European Space Agency (ESA), is designed for training astronauts underwater to simulate space gravity for the astronaut's extravehicular activities (EVAs). (Photo by Boris Horvat/AFP Photo)

This handout picture released by the Gagarin Cosmonauts' Training Centre on October 17, 2023 shows Marina Vasilevskaya (L) flying during a parabolic flight aboard a zero-gravity simulator, a Russian IL-76 MDK aircraft used for cosmonauts' training flights in weightlessness, in Star City outside Moscow. (Photo by Pavel Shvets/Gagarin Cosmonaut Training Center/AFP Photo)