A regional train passes fog-covered fields in Wehrheim near Frankfurt, Germany, early Friday, October 7, 2022. (Photo by Michael Probst/AP Photo)

Members of contemporary circus group perform inside the subway train, amid the energy crisis in Prague, Czech Republic on March 2, 2023. (Photo by David W. Cerny/Reuters)

A couple shares a light moment in a Mass Transit Railway (MTR) subway train in Hong Kong, China on August 28, 2019. (Photo by Anushree Fadnavis/Reuters)

Freshmen take part in a military training at Chongqing City Vocational College on September 23, 2021 in Chongqing, China. (Photo by Chen Shichuan/VCG via Getty Images)

A lenticular cloud is seen during sunrise from Gokmen Aerospace Training Center (GUHEM) in Bursa, Turkiye on January 19, 2023. (Photo by Halit Mirahmetoglu/Anadolu Agency via Getty Images)

Celera Barnes of the United States trains during a warm up session before the start of the World Athletics Indoor Championships at the Emirates Arena in Glasgow, Scotland, Thursday, February 29, 2024. (Photo by Bernat Armangue/AP Photo)

American paratroopers from the the 82nd Expeditionary Rescue Squadron take part in training for rescue operations in East Africa in the last decade of April 2024. (Photo by Senior Airman Olivia Gibson/US Air Force/CMA)

Members of the Hitler Youth who are trained to report airstrikes repaining their bicycles. Published by: “Die Sirene”. 1942. (Photo by Herbert Hoffmann/Ullstein Bild via Getty Images)