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)

Boats of fishermen are seen on the dried Poopo lakebed in the Oruro Department, south of La Paz, Bolivia, December 17, 2015. Lake Poopo in Bolivia, the Andean nation's formerly second largest after the famed Titicaca, has dried up entirely. With the water now gone, animals have died off in the millions, according to studies. And the local families, having lost much of their sustenance, have been forced to migrate. (Photo by David Mercado/Reuters)

In this Sunday, May 22, 2016 photo, contestants in the first Miss Trans Israel beauty pageant gather for rehearsal in Tel Aviv, Israel. The pageant will be held at HaBima, Israel's national theater, in Tel Aviv on Friday. Tel Aviv has emerged as one of the world's most LGBT-friendly travel destinations, standing in sharp contrast to most of the rest of the Middle East, where gays can face persecution. (Photo by Oded Balilty/AP Photo)

The Vietnam Slide Project was created by photo editor Kendra Rennick, who began collecting photo slides after a close friend lost her father, a Vietnam veteran. Her friend found a box of slides that her father had taken while in Vietnam and from there Rennick has continued to collect photographs that Vietnam veterans took during their tours of duty. Here: A photo taken from the collection of D.Thornton, who served in the First Air Cavalry division of the United States Army. (Photo by D.Thornton/The Vietnam Slide Project)

A visitor walks underneath a replica of a Titanosaur at the Cretaceous park in Cal Orcko, on the outskirts of Sucre, Bolivia, July 22, 2016. A footprint measuring over a meter wide that was made by a meat-eating predator some 80 million years ago has been discovered in Bolivia, one of the largest of its kind ever found. (Photo by David Mercado/Reuters)

Chocolate is the greatest gift the Earth has given us. The dessert table would be a sad sight without it. It’s so beloved, so appreciated, that the Swedish scientist who named the cocoa plant that gives us chocolate called it Theobroma cacao, which means “food of the gods”. Here: Farmer holding a freshly cut cocoa bean pod, revealing the pulp and seed inside on a rainforest farm. (Photo by Doug McKinlay/Getty Images)

A Syria Democratic Forces (SDF) fighter comforts a civilian who was evacuated with others by the SDF from an Islamic State-controlled neighbourhood of Manbij, in Aleppo Governorate, Syria, August 12, 2016. The SDF has said Islamic State was using civilians as human shields. (Photo by Rodi Said/Reuters)