Beach Policeman, Potomac River, 1922. (Photo by National Photo Company/Colorized by Patty Allison)

A sheep dressed in a jersey in the colors of the Colombian national soccer team is seen during a exhibition in Nobsa, Colombia June 1, 2014. The sheep is named Falcao, after the Colombian player. REUTERS/Jose Miguel Gomez

This undated photo shows the Arctic National Wildlife Refuge in Alaska. (Photo by U.S. Fish and Wildlife Service/Getty Images)

Tianmen Mountain is a mountain located within Tianmen Mountain National Park, Zhangjiajie, in northwestern Hunan Province, China.

Pupils look at an orphaned baby elephant at the David Sheldrick Elephant Orphanage within the Nairobi National Park, near Kenya's capital Nairobi October 15, 2014. The orphanage under the David Sheldrick Wildlife Trust is operated by Daphne Sheldrick, wife of late famous naturalist David William Sheldrick. The orphaned elephants raised by the trust will be returned to join the undomesticated elephant population in Tsavo National Park, where David was the founder warden from 1948 to 1976, when they mature, usually between eight to 10 years old. (Photo by Goran Tomasevic/Reuters)

The sun shines on trees that are displaying their autumn colours surrounding Palladian bridge and the lakeside Pantheon at the National Trust's Stourhead on November 3, 2010 near Warminster, England. (Photo by Matt Cardy/Getty Images)

Athletes of single bamboo drifting perform during the 9th National Traditional Games of Ethnic Minorities of the People's Republic of China on September 11, 2011 in Guiyang, China. (Photo by Feng Li/Getty Images)

A runner traverses the route during the Mount Everest Challenge Marathon which winds past spectacular views of Everest and Kanchenjunga at Sandakphu National Park in the month of November 1995 near Darjeeling, India.