Wakhi nomad women milk yaks in Wakhan, Afghanistan. About 12,000 villagers live at an altitude of 4,500 metres in the harsh, desolate terrain. The Wakhi people live a simple, relaxed life with their livestock. (Photo by Eric Lafforgue/Barcroft Images)

This April 30, 2016 image made available by NOAA shows a deep sea anglerfish living between pillow basalt rock formations, during a deepwater exploration of the Marianas Trench Marine National Monument area in the Pacific Ocean near Guam and Saipan. The ambush predator waits for prey to be attracted by its lure, located between its eyes, and gulps it with its large mouth. (Photo by NOAA Office of Ocean Exploration and Research via AP Photo)

U.S. Rep Steve Southerland grins after winning an auctioned possum during the Wausau Possum Festival on Saturday, August 2, 2014, in Wausau, Fla. What is usually a must-attend event for statewide candidates was notably lacking of them this year, perhaps because candidates who now raise tens of millions of dollars focus more on television ads than making personal contact. But not attending is a missed opportunity, said Susan MacManus, a University of South Florida political science professor who drove more than 350 miles for the festival. (Photo by Heather Leiphart/AP Photo/The News Herald)

A boy jumps from a swing during sunset in Valras-Plage, southern France December 29, 2014. (Photo by Yves Herman/Reuters)

Rick Sorenson, owner of the Rio Ramaza Marina, wades in the Sacramento River after securing an old paddlewheel boat on his property as the river makes its way up the levee on Garden Highway in Sacramento, Calif., Monday, January 9, 2017. (Photo by Hector Amezcua/The Sacramento Bee via AP Photo)

Children hold signs thanking truck drivers hauling rocks to the Lake Oroville Dam after an evacuation was ordered for communities downstream from the dam in Oroville, California, U.S. February 13, 2017. (Photo by Jim Urquhart/Reuters)

A baby elephant eats in a swamp in Amboseli national park, Kenya, March 19, 2017. (Photo by Goran Tomasevic/Reuters)

A Pakistani labourer carries bricks on his back at a construction site at a residential area in Islamabad on March 29, 2017. (Photo by Aamir Qureshi/AFP Photo)