Students exercise in body training at Bishan Vocational Education Center in Chongqing, southwest China, January 13, 2016. These students were trained to be stewardesses of the high-speed train. (Photo by Xie Jie/Xinhua)

Women perform a pole dancing routine during the national day celebration of “Urban Pole” dance along a street in Monterrey, Mexico, on June 9, 2013. (Photo by Daniel Becerril/Reuters)

Model Chanel Iman arrives on the red carpet for the screening of the film “Hands of Stone” out of competition at the 69th Cannes Film Festival in Cannes, France, May 16, 2016. (Photo by Yves Herman/Reuters)

A guard dog in the suburbs of Yakutsk, Russia, considered to be the coldest city in the world, January 2014. (Photo by Amos Chapple/REX Features)

A child walks to an installation made from fallen leaves by college students, in shape of a sofa, to call for people's attention to environment protection, in Hangzhou, Zhejiang province, China, December 6, 2016. (Photo by Reuters/China Daily)

A boy walks with toy guns as people ride an APC during a military show at the Finnish Gulf coast in St.Petersburg, Russia, Saturday, September 5, 2015. (Photo by Dmitry Lovetsky/AP Photo)

A 10 week old stuffed Tiger cub and a Tortoise are displayed in a cabinet at an “Endangered Species” exhibition at London Zoo on September 12, 2011 in London, England. The exhibition is organised by “Operation Charm”, a Metropolitan Police partnership aimed at tackling the illegal trade in endangered wildlife and runs for one month at London Zoo. Items include the tooth of a sperm whale, Ivory carvings, and a stuffed Tiger. (Photo by Dan Kitwood/Getty Images)

In this November 9, 2014 photo, a man sits on the rope holding his bull by the neck as he waits to enter it in a bull fight in Leogane, Haiti. The obscure Haitian practice of fighting bulls is brutal like a cock or dog fight, but on a larger scale. A casual pastime for some rural men, it is serious business for others looking to pay their children's school fees or even buy a car. (Photo by Dieu Nalio Chery/AP Photo)