Students attend a stewardess skill training for the upcoming 2017 entrance examination for art majors in colleges in Luoyang, central China's Henan Province, January 4, 2017. Along with how to stand, how to sit is also covered in these classes. (Photo by Li Bo/Xinhua/Barcroft Images)

Revelers of the “Societe des Champs Elysee” launch fireworks before boarding the Rampart-St. Claude street car line, which just opened last fall, to commemorate the official start of Mardi Gras season, in New Orleans, Friday, January 6, 2017. (Photo by Gerald Herbert/AP Photo)

Passengers prepare to take part in the No Pants Subway Ride in Prague, Czech Republic, Sunday, January 8, 2017. The No Pants Subway Ride began in 2002 in New York as a stunt and has taken place in cities around the world since then. (Photo by Petr David Josek/AP Photo)

A representative of Makinarium production, specialized in special visual effects, displays a latex mask for horror movie on a stand inside the Festival Palace during the 69th Cannes Film Festival in Cannes, France, May 14, 2016. (Photo by Regis Duvignau/Reuters)

An officer reviews members of the honor guard as they line up before a welcoming ceremony for visiting Mozambique's President Filipe Jacinto Nyusi at the Great Hall of the People in Beijing, Wednesday, May 18, 2016. (Photo by Mark Schiefelbein/AP Photo)

People look at the Turrialba volcano as it spewes ashes on May 20, 2016, in Cartago, Costa Rica. The Turrialba volcano started erupting columns of smoke and ash that the wind extended towards the Costa Rican capital, in what according to experts is the strongest eruption in the past six years. (Photo by Ezequiel Becerra/AFP Photo)

(L-R) Recording artists Ally Brooke, Normani Hamilton, Dinah-Jane Hansen, Lauren Jauregui and Camila Cabello of Fifth Harmony attend the 2016 Billboard Music Awards at T-Mobile Arena on May 22, 2016 in Las Vegas, Nevada. (Photo by David Becker/Getty Images)

Visitors at the National Zoo check out a parrotfish made from found waste from the ocean in Washington, DC on May 23, 2016. The artwork can be seen at the National Zoo until September 5th. (Photo by Keith Lane/The Washington Post)