A paramilitary police officer (right) turns around as hostesses line up for roll call ahead of the Beijing International Automotive Exhibition in Beijing, China, on Monday, April 25, 2016. Tesla Motors Inc. and BYD Co. are among manufacturers showing 147 new-energy vehicles at this year's show. (Photo by Qilai Shen/Bloomberg)

Lawmakers from the main opposition Republican People's Party (CHP) and ruling AK Party (R) scuffle during a debate on a legislation to boost police powers, at the Turkish Parliament in Ankara, Turkey, February 19, 2015. (Photo by Reuters/Stringer)

Katy Perry poses backstage during rehearsals for the 2017 MTV Video Music Awards at The Forum on August 25, 2017 in Inglewood, California. (Photo by John Shearer/Getty Images for MTV)

The Aurora Borealis (Northern Lights) lights up the sky near the village of Pallas (Muonio region) of Lapland, Finland September 8, 2017. (Photo by Alexander Kuznetsov/Reuters/All About Lapland)

A general view shows smoke and volcanic ashes billowing from volcano Cotopaxi in Pedregal, Ecuador, late 07 October 2015. (Photo by Jose Jacome/EPA)

Young man making the O.K. sign. (Photo by George Marks/Retrofile/Getty Images). Circa 1950s

British born leading lady Elizabeth Taylor feeds the pigeons in Trafalgar Square, London. (Photo by Chris Ware/Keystone/Getty Images). November 1948

Children of the Roma community play as they cool off in a fountain in the main square of Pristina, Kosovo on June 14, 2017. (Photo by Armend Nimani/AFP Photo)