Soldiers of People's Liberation Army (PLA) Lanzhou Military Region jump through a burning obstacle during a training session at a military base in Tianshui, Gansu province, China, January 6, 2016. (Photo by Reuters/Stringer)

Two biplanes of the Team Breitling cross during a training flight prior the AIR14 air show in Payerne, Switzerland, August 29, 2014. (Photo by Peter Schneider/EPA)

A picture taken with slow shutter speed shows members of the group “The Kattfiller” from Attendorn taking part during the Norddeutsche Championship carnivalesque dance sport in Kassel (Hessen), Germany, 28 February 2016. About 1,100 qualified dancers show in different disciplines their skills. (Photo by Swen Pfoertner/EPA)

Two young boys kneel on stools on either side of a round table as one uses a match to this the other's cigarette, November 12, 1928. (Photo by FPG/Getty Images)

Florin Bors, aged 8 from Bacau, northern Romania, wearing a bear fur takes a break from performing a holiday season ritual in Bucharest, Romania, Tuesday, December 16, 2014. In pre-Christian rural traditions, dancers wearing colored costumes or animal furs, touring house to house in villages singing and dancing to ward off evil. In recent years following the economic downturn in Romania, a European Union member since 2007, the tradition has moved to Romania's cities where dancers travel to perform the ritual for money. (Photo by Octav Ganea/AP Photo/Mediafax)

Actors dressed up as zombies walk around while posing for photos with passers-by in New York's Times Square on Friday, October 10, 2014 as a promotion for the season premiere of AMC's “The Walking Dead” this Sunday, October 12, 2014. (Photo by Gordon Donovan)

Alee Harrison, 13, wears the tv series “Doctor Who” on her legs as she works on a painting for Operation Blue Pride. (Photo by Greg Lovett/The Palm Beach Post)

A bull rams inmates seated at a card table in the Convict Poker event at the Angola Prison Rodeo in Angola, La., Saturday, April 26, 2014. Those competing in the rodeo have to pass a physical to be deemed strong and healthy enough, and thousands of others work year-round making arts and crafts to sell at the event, according to the prison's athletic director. (Photo by Gerald Herbert/AP Photo)