Ukrainian state emblem is seen on a gun's holster as soldiers guard naval base in the village of Novoozernoye, some 91 km west of Crimean capital Simferopol, Ukraine, on Monday, March 3, 2014. Ukraine says Russian forces controlling the strategic region of Crimea are demanding that the crew of two Ukrainian warships in Sevastopol's harbor must surrender. (Photo by Ivan Sekretarev/AP Photo)

“Aurora Hunters”. Photographers taking part in a photography tour on the Lofoten Islands in Norway, pull over on the side of the road to take a photo of their first ever Aurora Borealis after spotting it from their tour bus. Photo location: Rystad, Lofoten Islands, Norway. (Photo and caption by Mark Gee/National Geographic Photo Contest)

Buyan, a male Siberian brown bear, is given a shower by a zoo employee in his enclosure at the Royev Ruchey zoo in Russia's Siberian city of Krasnoyarsk June 24, 2014. The Siberian city has been experiencing temperatures of around 30 degrees Celsius over the last week. (Photo by Ilya Naymushin/Reuters)

A model walks the runway during the Versace show as part of Paris Fashion Week Haute Couture Spring/Summer 2015 on January 25, 2015 in Paris, France. (Photo by Pascal Le Segretain/Getty Images)

Doutzen Kroes and Candice Swanpoel arrive at the Mert Alas x Marcus Piggot book launch party at Public Hotelon September 7, 2017 in New York City. (Photo by Pierre Suu/GC Images)

A horse named Quinn, with a skeleton painted on it to help educate officers, is pictured during a visit by Britain's Queen Elizabeth II (unseen) and Britain's Prince Charles, Prince of Wales (unseen) to the Household Cavalry Mounted Regiment at the Hyde Park Barracks in west London on October 24, 2017. (Photo by Chris Jackson/AFP Photo)

A pole-dancing robot built by British artist Giles Walker performs at a gentlemen's club Monday, January 8, 2018, in Las Vegas. The event was held to coincide with CES International. (Photo by Jae C. Hong/AP Photo)

A hillside erupts in flame as a raging wildfire fire burns in Placerita Canyon in Santa Clarita, Calif., Monday, July 25, 2016. A raging wildfire that forced thousands from their homes on the edge of Los Angeles continued to burn out of control Monday as frustrated fire officials said residents reluctant to heed evacuation orders made conditions more dangerous and destructive for their neighbors. (Photo by Nick Ut/AP Photo)