Gunung Leuser National Park is a national park covering 7,927 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after Mount Leuser (3,381 m), protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park. Together with Bukit Barisan Selatan and Kerinci Seblat national parks it forms a World Heritage Site, Tropical Rainforest Heritage of Sumatra.

Participants wrestle while riding yaks during Kyrgyz national horse games and festival near the Tulpar-Kul in the Chon Alai range, some 3500 metres (11483 feet) above sea level, Osh region, Kyrgyzstan, July 25, 2015. (Photo by Vladimir Pirogov/Reuters)

A Saddle-billed Stork is seen in Amboseli National park, Kenya, February 10, 2016. (Photo by Goran Tomasevic/Reuters)

The Zhangjiajie National Forest Park is a unique national forest park located in Zhangjiajie City in northern Hunan Province in the People's Republic of China. It is one of several national parks within the Wulingyuan Scenic Area.

Nepalese students of Himalayan agriculture college play in mud water in a paddy field to celebrate the National Paddy Day in Badegaun village, Lalitpur, Nepal, 29 June 2016. More than 100 students and teachers of Himalayan agriculture college participated in the National paddy day by planting rice and playing in mud water as Nepal is celebrating National Paddy Day with various event. (Photo by Narendra Shrestha/EPA)

Glacier National Park is a national park located in the U.S. state of Montana, on the Canada–United States border with the Canadian provinces of Alberta and British Columbia. The park encompasses over 1,000,000 acres (4,000 km2) and includes parts of two mountain ranges (sub-ranges of the Rocky Mountains), over 130 named lakes, more than 1,000 different species of plants and hundreds of species of animals. This vast pristine ecosystem is the centerpiece of what has been referred to as the "Crown of the Continent Ecosystem", a region of protected land encompassing 16,000 square miles (41,000 km2).

(L-R) Natalie Burns and Taunia Arave battle as referee Nick Stevens (R) looks on during the US National Sumo Championships at the Riviera Hotel & Casino June 24, 2011 in Las Vegas, Nevada. (Photo by Ethan Miller/Getty Images)