Fifth-grade students of the General Yermolov Cadet School get prepared before their first military tactical exercise on the ground, which includes radiation resistance classes, forest survival studies and other activities, in Stavropol, Russia, September 10, 2016. Picture taken September 10, 2016. (Photo by Eduard Korniyenko/Reuters)

A Palestinian youth demonstrates his parkour skills on a street in Gaza City, January 15, 2016. (Photo by Suhaib Salem/Reuters)

A participant competes in the “Farinato Race” winter extreme run competition in Gijon, northern Spain, January 31, 2016. (Photo by Eloy Alonso/Reuters)

Labourers carry a basket packed with vegetables through a wholesale market in Kolkata, India, February 26, 2016. (Photo by Rupak De Chowdhuri/Reuters)

A child plays with a plastic badminton racket in the old quarters of Delhi, India, March 3, 2016. (Photo by Anindito Mukherjee/Reuters)

Participants pose during a local bodybuilding and fitness championship in Karachi, Pakistan March 13, 2016. (Photo by Akhtar Soomro/Reuters)

A man exercises in the early morning on a hilltop overlooking Kabul, Afghanistan March 3, 2016. (Photo by Mohammad Ismail/Reuters)

Young U.S. visitors pose for a photograph next to a vintage car in Havana March 16, 2016. (Photo by Ueslei Marcelino/Reuters)