Koreans spin fire cans during “Jwibulnoli” a South Korean folk game at Han River on February 5, 2012 in Seoul, South Korea. The event is part of a “Daeboreum”, a Korean holiday that celebrates the first full moon of the lunar new year. (Photo by Chung Sung-Jun/Getty Images)

A simulated casualty is evacuated during an emergency services exercise at the disused Aldwych underground station on February 22, 2012 in London, England. Operation Forward Defensive aims to test the response to a terrorist incident on the London Underground network during the 2012 Olympic Games. (Photo by Peter Macdiarmid/Getty Images)

A cat jumps from a shelf to catch a light beam at the “Kis-Kis” Cat Cafe in the Siberian city of Krasnoyarsk, Russia, July 6, 2015. A local animals rights group founded the shelter for dozen of homeless cats and combined it with the cafe, where visitors can communicate with animals for hourly fee in addition to drinks, table games, books and WI-FI. (Photo by Ilya Naymushin/Reuters)

A woman attends a boxing class at Princess Women's Boxing Club in Shanghai December 3, 2014. Women have boxed as long as the sport has existed but for years they were relegated out of national and international competitions in many countries around the world. Female boxers entered the ring in an exhibition match at the 1904 Olympic Games, but it was more than a century later when they were given the green light to make their Olympic debut in London in 2012. (Photo by Carlos Barria/Reuters)

In this July 11, 2016 photo, a young, masked drug trafficker poses for photos holding his guns at a slum in Rio de Janeiro, Brazil. Teenagers openly tote guns while they work as guards, lookouts and distributors for drug lords operating just a few miles from where hundreds of thousands and tourists and athletes will be for the Aug. 5-21 Olympic Games. (Photo by Felipe Dana/AP Photo)