Sandstone sculpted by water and wind erosion is seen in a slot canyon, one of hundreds that surround Lake Powell near Page, Arizona, May 26, 2015. Lake Powell on the Colorado River provides water for Nevada, Arizona and California. A severe drought in recent years, combined with withdrawals that many believe are not sustainable, has reduced its levels to only about 42 percent of its capacity. (Photo by Rick Wilking/Reuters)

Natalia Arango works with her mine detector in a zone of landmines planted by rebels groups near Sonson in Antioquia province, November 19, 2015. Women's work takes on a nontraditional meaning for fifteen Colombian women who work to rid the Antioquia Mountains of deadly landmines as the country edges closer to a peace agreement with Marxist rebels to end over a decade of conflict which has claimed 220,000 lives. (Photo by Fredy Builes/Reuters)

In this handout provided by the National Aeronautics and Space Administration (NASA), SpaceX's Falcon 9 is moved to the launch pad prior to the rocket's Thales Alenia Space launch attempt on April 26, 2015 in Cape Canaveral, Florida. (Photo by NASA via Getty Images)

These images offer a rare glimpse of life within remote Brazilian tribes. Award winning photographer Ricardo, 47, said: “The pictures show the traditional way of life of these people who live in harmony with nature. The photos provide an overview of the contemporary situation of the indigenous people in Brazil”. Here: Bej indian in the Xingu river, state of Mato Grosso, Brazil on December 20, 2015 .(Photo by Ricardo Stuckert/Caters News Agency)

Documentary photographer William E. Crawford was one of the first Western photographers to gain access to North Vietnam after the war ended. He has photographed the capital, Hanoi, at regular intervals since 1985, concentrating on the colonial and indigenous architecture, urban details, landscapes and intimate portraits of people in their home settings, street scenes and the city’s surrounding countryside. Here: 54 Hàng Ga (Chicken Street), 1994. (Photo by William E. Crawford from the book “Hanoi Streets 1985-2015: In the Years of Forgetting”)

In this November 12, 2015, file photo, Mt. Everest is seen from the way to Kalapatthar in Nepal. An American climber has died near the summit of Mount Everest and an Indian climber is missing after heading down from the mountain following a successful ascent, expedition organizers said Sunday. (Photo by Tashi Sherpa/AP Photo)

Rungis is a commune in the southern suburbs of Paris, France. It is best known as the location of the large wholesale food market serving the Paris metropolitan area and beyond, the Marché d'Intérêt National de Rungis, said to be the largest food market in the world. The name Rungis was recorded for the first time in a royal charter of 1124 as Rungi Villa. Here: swordfish are sold at the fish pavilion in Rungis International food market as buyers prepare for the Christmas holiday season in Rungis, south of Paris, December 11, 2015. (Photo by Philippe Wojazer/Reuters)

Men dressed as “Krampuss” prepare to parade at Munich's Christmas market, December 13, 2015. Young single men will wear the traditional attires known as “Krampusse”, consisting of animal skins and masks, with large cow-bells to make loud and frightening noises and parade through the city. They follow “Saint Nicholas” from house to house in December each year to bring luck to the good and punish the idle. (Photo by Michael Dalder/Reuters)