A tourist poses on the glass-bottom bridge at Zhangjiajie Grand Canyon on August 20, 2016 in Zhangjiajie, Hunan Province of China. The Zhangjiajie Grand Canyon's glass-bottomed bridge welcame its trial operation on Saturday and about 8,000 tourists crowded to view the grand glass bridge. (Photo by VCG/VCG via Getty Images)

This picture taken on May 21, 2016 shows professional wrestlers fighting each other during the Wrestling City Asia organized by Singapore Pro Wrestling at a stadium in Kuala Lumpur. Kenneth Thexeira is a mild-mannered writer for an interior-design magazine by day, but on certain nights his alter ego bursts forth in golden tights and a baby-blue cape: enter “The Eurasian Dragon”. (Photo by Mohd Rasfan/AFP Photo)

Revellers attend the Play Time 2016 music festival on the outskirts of Ulaanbaatar, Mongolia, June 26, 2016. (Photo by Jason Lee/Reuters)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Bathing suit models are shown listening to the radio on the beach, circa 1940's. (Photo by Bettmann Archive/Getty Images)

A Minion character dressed in a Christmas theme is pictured in Times Square during unseasonably warm weather on Christmas Eve in the Manhattan borough of New York, December 24, 2015. (Photo by Carlo Allegri/Reuters)

Black-headed gulls sit on pickets at a riverside in Tokyo, Japan, December 27, 2015. (Photo by Toru Hanai/Reuters)

A Monster Jam truck performs a back flip during the first-ever monster truck event in Beijing's iconic “Bird's Nest” National Stadium on Saturday, July 29, 2017. (Photo by Ng Han Guan/AP Photo)