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)

Northeastern girls getting commando training at the Delhi Police Training Centre, Jharoda Kalan on September 4, 2017 in New Delhi, India. For the first time ever, Delhi Police are providing commando training to 40 young women from the Northeast. Once the commando training is over, these girls will be a part of the «Parakram Vans», an initiative taken by Delhi Police against terrorism. (Photo by Manoj Verma/Hindustan Times via Getty Images)

Marines finish a 10 kilometer training hike carrying 55 pound (25 kg) packs during Marine Combat Training (MCT) on February 22, 2013 at Camp Lejeune, North Carolina. Since 1988 all non-infantry enlisted male Marines have been required to complete 29 days of basic combat skills training at MCT after graduating from boot camp. MCT has been required for all enlisted female Marines since 1997. About six percent of enlisted Marines are female. (Photo by Scott Olson/AFP Photo)

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)

Hwang Bo-young (L), a North Korean defector who was a member of the North Korean National female ice hockey team, prepares for practice with South Korean teammates on March 13, 2006 in Seoul, South Korea. Young, 27-years-old, became a captain of the South Korean National Female Ice Hockey Team. (Photo by Chung Sung-Jun/Getty Images)

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)

Underwater photographer Sarah Lee uses a technique known as “duck diving” to capture these stunning photos of surfers in Hawaii. Surfers “duck dive” under the water to avoid incoming waves so they can get further out to sea. Photo: A surfer comes free from her surfboard. (Photo by Sarah Lee/Caters News)