U.S. Army soldiers with the 1st Battalion, 501st Infantry Regiment deployed to Combat Outpost Sabari, Afghanistan scan their area as they begin a multi-day air assault mission near the Pakistani border of eastern Afghanistan's Khost province May 2, 2012. (Photo by Staff Sgt. Joshua L. DeMotts/U.S. Air Force)

Soldiers of Ukraine's National Guard 1st brigade Bureviy (Hurricane) fire a recoilless cannon during combat training at a military training ground in the north of Ukraine Friday, November 3, 2023. (Photo by Efrem Lukatsky/AP Photo)

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 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)

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