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)

The rarely seen blue sharks photographed by Saeed Rashid in British waters. Elusive blue sharks have recently been spotted off the south coast of England, having moved to the UKs warmer waters to hunt. The carnivorous sharks have been lurking off the coast of the popular British holiday destination, Penzance, in Cornwall. (Photo by Saeed Rashid/Caters News)

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)

Mystical Forest. Tracey Jennings photographed this seven-gill shark in a kelp forest just off the shore of Simon's Town near Cape Town, South Africa. You don't need to travel far from cities to visit Narnia. This 7 gill shark was photographed in a kelp forest just off the shore of Simonstown near Cape Town, South Africa. (Photo by Tracey Jennings/National Geographic Travel Photographer of the Year Contest)

A couple sunbath on the beach in Ostrowo, northern Poland, July 20, 2015. Picture taken July 20, 2015. (Photo by Kacper Pempel/Reuters)

One-day-old baby giraffe calf Gus looks at the camera at Noah's Ark farm on May 12, 2017 in Bristol, England. The baby giraffe was born yesterday at the zoo farm in North Somerset. In the wild, populations of giraffes are suffering from a continuing decline, with 97,500 estimated in Africa in 2015. Since 1985 the total giraffe population has fallen by 35%. New arrival Gus joins brothers George, 4 and Geoffrey, 2. (Photo by Matt Cardy/Getty Images)

A cyclist drives past a flowering rapeseed field not far from the small Bavarian village of Schoengeising, near Munich, during a nice, warm sunny weather day on May 17, 2017. (Photo by Christof Stache/AFP Photo)

A man walks on the road between Nouahibou and Nouakchott, where three Spanish aid workers were abducted in Mauritania, December 3, 2009. (Photo by Rafael Marchante/Reuters)