Framed by the setting sun, an American Bison grazes at the Tallgrass Prairie National Preserve on Tuesday, April 28, 2015, near Strong City, Kan. The buffalo herd at Tallgrass is one of the few herds of wild bison left in the United States. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

People look at huge waves crashing on the San Esteban de Pravia seafront, northern Spanish region of Asturias February 8, 2016. (Photo by Eloy Alonso/Reuters)

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)

Venezuela: An anti-government protester wearing a Guy Fawkes mask throws a molotov cocktail at the Bolivarian National Police during clashes in Caracas, Venezuela, Thursday, April 17, 2014. Opposition protesters have been demonstrating against high crime, high inflation and shortages of basic goods since mid-February. (Photo by Ramon Espinosa/AP Photo)

A grave cleaner holds up a skull during exhumation works at the Cemetery General in Guatemala City May 24, 2013. If a lease on a grave has expired or not been paid, grave cleaners will break open the crypts to remove and rebury the bodies. (Photo by Jorge Dan Lopez/Reuters)

In this Wednesday, September 17, 2014 photo, the sun shines over a field of sunflowers in Walkill, N.Y. (Photo by John DeSanto/AP Photo/Times Herlad-Record)

This bat gives a cheeky smile as he gobbles down his food at Singapore Zoo, on September 10, 2013. (Photo by Benny Iskander/HotSpot Media)

Super-cell thunderstorms, whirling tornados and lightning bolts illuminating the sky – these photos capture the terrifying brilliance of American storms. (Photo by Brandon Goforth/Solent News & Photo Agency)