Young Buddhist novice monks play at a Tibetan nomadic summer grazing area on July 24, 2015 on the Tibetan Plateau in Yushu County, Qinghai, China. Tibetan nomads face many challenges to their traditional way of life including political pressures, forced resettlement by China's government, climate change and rapid modernization. The Tibetan Plateau, often called “The Roof of the World”, is the world's highest and largest plateau. (Photo by Kevin Frayer/Getty Images)

Arnaq Egede walks to the potato field on her family's farm on July 31, 2013 in Qaqortoq, Greenland. The farm, the largest in Greenland, has seen an extended crop growing season due to climate change. (Photo by Joe Raedle/Getty Images)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

If the most popular foods of Rio de Janeiro have one thing in common, it is their informality. You can find fine restaurants in the city, but they do not set Rio apart from other places. What does set it apart, and what invariably brings its residents, known as "Cariocas," together is the unpretentious food they eat in bright, loud, crowded bars and restaurants, on busy street corners, or after a day at the beach. Here: A view of traditional bolinhos de bacalhau (fried codfish balls) in Rio de Janeiro, Brazil, May 7, 2016. (Photo by Sergio Moraes/Reuters)

Resident Taina holds her brother Ysaque in the hallway outside their apartment in an occupied building in the Mangueira “favela” community on August 13, 2016 in Rio de Janeiro, Brazil. (Photo by Mario Tama/Getty Images)

A visitor celebrates after attending a bare hand fishing event in a frozen river during the Hwacheon Sancheoneo Ice Festival at Hwacheon-gun, Gangwon province, South Korea, 09 January 2016. The festival runs under the theme “Unfrozen Hearts, Unforgettable Memories” from 09 January to 31 January 2016. (Photo by Jeon Heon-Kyun/EPA)

A schoolgirl is soaked with water thrown by an elephant in a preview of the upcoming Songkran Festival celebration, the Thai traditional New Year, also known as the water festival in the ancient world heritage city of Ayutthaya, Thailand, 11 April 2016. The annual elephant Songkran is held to promote the tourism industry prior the three-day Songkran Festival which starts on 13-15 April annually and is celebrated with splashing water and putting powder on each others faces as a symbolic sign of cleansing and washing away the sins from the old year. (Photo by Diego Azubel/EPA)

Professional conceptual category winner. Greetings from Mars, by Julien Mauve, France. Mauve says: “I have always wondered what it would be like to discover a totally different world ... and to photograph it for the first time as if I was Ansel Adams. So I came up with this project, which is about space exploration and discovery. But it’s also about our behavior in front of landscapes and how we create pictures that will share our personal story with the world”. (Photo by Julien Mauve)