Inmates dressed as Santa Claus prepare to participate in an event ahead of Christmas celebrations at Santa Monica female prison in Lima December 19, 2014. (Photo by Enrique Castro-Mendivil/Reuters)

U.S. soldiers wrestle with South Korean soldiers in a muddy ring during a joint ranger training exercise at a ranger camp near the demilitarised zone (DMZ) June 25 2003 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

Indian soldiers practice their stunts on Royal Enfield motorcycles in preparation for the upcoming Republic Day parade on January 11, 2012 in New Delhi, India. (Photo by Daniel Berehulak /Getty Images)

Afghan police recruits undergo training at the Afghan Police Academy October 5, 2010 in Kabul, Afghanistan. (Photo by Majid Saeedi/Getty Images)

Female Competitors pose onstage during the annual Mr. Korea competition on July 7, 2004 in Seoul South Korea. Mr. Korea, organized by the National Body Builder's Association, is one of the biggest bodybuilding competitions in Asia. (Photo by Chung Sung-Jun/Getty Images)

Lucha libre is Mexico’s version of what in the United States refer to as pro wrestling. Its dates to 1863, when a Mexican wrestler named Enrique Ugartechea developed a form of “freestyle” wrestling that was based on Greco-Roman wrestling. Lucha libre began to soar in popularity in Mexico after two Italian businessmen started promoting fights in the early 1900s. It has since become popular around the globe. Here: Juliza meets with colleagues at her home. (Photo by Diana Bagnoli/The Washington Post)

Mariam Emad from Parkour Egypt “PKE” practices her parkour skills around buildings on the outskirts of Cairo, Egypt on July 20, 2018. A group of Egyptian women gather at an abandoned park in a Cairo suburb once a week, climbing walls and jumping around in the strenuous physical discipline known as Parkour, while also challenging the country's conservative social norms. (Photo by Amr Abdallah Dalsh/Reuters)

A young YPJ recruit (in pink) arrives to the training base for her first day in training near Derek City, Syria. The YPJ schedule is demanding and requires discipline – new soldiers in training get about 6 hours of sleep a night and wake up at 4 AM to begin exercising; afterwards, their day consists of a full schedule of drills and classroom lessons. Before joining the YPJ many of the girls had never participated in physical activity or sports before. (Photo by Erin Trieb/NBC News)