A zebra walks through the recently flooded Safari Park located at Safari World November 2, 2011 in Bangkok, Thailand. (Photo by Paula Bronstein /Getty Images)

A child dressed as a cat takes part in the Children's Halloween day parade at Washington Square Park in the Manhattan borough of New York October 31, 2015. (Photo by Carlo Allegri/Reuters)

Kangba women carry barrels to fetch water at a village on April 10, 2005 in Zuogong County of Tibet, China. Kangba people began to fetch water with the traditional barrels hundreds of years ago. Kangba people are one of the Tibetan tribes living in Kangba Region, a juncture area of Sichuan and Yunnan Provinces and the Tibet Autonomous Region. Kangba people are famous for their beauty, toughness and straightforwardness. (Photo by China Photos/Getty Images)

Six month- old baby elephant “Clear Sky” is kept afloat with the help of a harness during a hydrotherapy session at a local veterinary clinic in Chonburi Province on January 5, 2017. After losing part of her left foot in a snare in Thailand, baby elephant 'Clear Sky' is now learning to walk again – in water. (Photo by Roberto Schmidt/AFP Photo)

A dancer from the Trisha Brown Dance Company performs during “Roof Piece” above the High Line park June 9, 2011 in New York City. Roof Piece (1971) consists of nine dancers performing improvised movement signals to each other in a chain on various rooftops overlooking the city. This presentation marked the first full performance of the piece since 1973. (Photo by Mario Tama/Getty Images)

Children play at the Ryoji Ikeda exhibition “the transfinite” at the Park Avenue Armory on June 10, 2011 in New York City. The audio visual installation, which will close after tomorrow, features two back-two-back screens displaying a continual loop of sounds, fragments of numbers and strobe-lit patterns that echo the Japanese artist's interest in mathematics, the subconscious and the digital world. (Photo by Spencer Platt/Getty Images)

View of colourful rock formations at the Zhangye Danxia Landform Geological Park in Gansu Province, China. The Zhangye Danxia Landform Geological Park is 40km from Zhangye city. The park spans more than 400 square kilometers in Gansu. The unusual terrain is the result of red sandstone and mineral deposits carved over the years by natural forces. (Photo by ImagineChina/The Grosby Group)

Winner of the National Park Foundation's photo contest; Honorable Mention: Fan Favorite. Grand Canyon National Park, Arizona. Three friends enjoy sunrise over the Grand Canyon. (Photo by Peter Blanchard)