5. Underwear Run
Participants run during the NYC Triathlon's Underwear Run, a 1.7-mile fun-run, in Central Park in New York City, the United States, on July 14, 2017. (Xinhua/Li Muzi)
"Naked Pig Run" -- Participants in "Naked Pig Run" event need to strip down to their underwear in wintry conditions. It aims to raise awareness of sustainable living and harmony with nature.
Participants run at the annual "naked pig run" at Olympic Forest Park in Beijing, China, Feb. 26, 2017. (Xinhua/Liu Xianguo)
