British model Demi Rose leaving Bob Bob Ricard on November 20, 2017 in London, England. (Photo by Splash News and Pictures)

A demonstrator catches fire during clashes with riot police within a protest against Venezuelan President Nicolas Maduro, in Caracas on May 3, 2017. Venezuela's angry opposition rallied Wednesday vowing huge street protests against President Nicolas Maduro's plan to rewrite the constitution and accusing him of dodging elections to cling to power despite deadly unrest. (Photo by Ronaldo Schemidt/AFP Photo)

An Army Sikorsky R-5 helicopter, undergoing record trials, demonstrates its lifting power by carrying 17 persons and pilot aloft as female onlookers wave in Bridgeport, Conn., January 10, 1946. During the tests records were claimed for altitude speed and both altitude and speed with payload. (Photo by Anthony Camerano/AP Photo)

Subway passengers walk past bronze sculptures representing the Soviet people at the Ploshchad Revolyutsii metro station in Moscow, on November 14, 2012. The station was opened in 1938. (Photo by Kirill Kudryavtsev/AFP Photo)

American soldiers with the 173rd Airborne Brigade Battle Company, on a battalion-wide mission in the Korengal Valley, looking for caves, weapons caches and known Taliban leaders, 2007. Tanner Stichter tends to Spc. Carl Vandeberge in the bushes moments after Vandeberge was shot in the stomach during a Taliban ambush, which killed one soldier and wounded two others. (Photo by Lynsey Addario)

In this September 17, 2010 file photo a little brown bat is photographed in La Crosse Wis. Researchers for the first time found that little brown bats appear to be showing resistance to white-nose syndrome, which has killed millions of bats across North America. (Photo by Peter Thomson/La Crosse Tribune via AP Photo)

To the woman presented a flower in Sevastopol, Ukraine, on March 8, 2013. Activists presented this day on the street free 155 tulips to women. The police tried to arrest activists for illegal trade as couldn't believe in free distribution of flowers. (Photo by Sergey Anashkevitch)

“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)