A Unidie Run competition is held in Nanjing, capital of southeast China's Jiangsu province, Jan. 11, 2014. Nearly 100 runners wearing almost nothing but their underwear ran around the Xuanwu Lake. The participants wanted to call on the public to get closer to the nature and live a healthy life by this activity.

Originating in the U.S., Unidie Run is an event where a large number of people disrobe until they are only wearing underwear, and then run. In recent years, this activity gains great popularity in China.