Riders negotiate a dune as they compete in the Adult Solo race at the HydroGarden Weston Beach Race in Weston- super- Mare, south west England, on October 9, 2016. Beach racing is an offshoot of enduro and motocross racing. Riders on solo motorcycles and quad bikes compete on a course marked out on a beach, with man- made jumps and sand dunes being constructed to make the course tougher. (Photo by Adrian Dennis/AFP Photo)

In this Saturday, March 21, 2015 photo, a porter rests carrying supplies for the upcoming climbing season, near the Everest Base camp, Nepal. Nepal has cleared more than 300 mountaineers to climb Mount Everest after they had to abandon last year's efforts when an ice avalanche killed 16 guides in the mountain's deadliest disaster, an official said on March 20. The three-month climbing season for Everest, the world's tallest mountain, begins in March. (Photo by Tashi Sherpa/AP Photo)

“These eerie formations in the sky may look like alien ships. But as the Daily Mail points out, they’re actually a natural occurrence called lenticular clouds”. – Claudine Zap. Photo: Lenticular clouds hover of the mountains of the Kamchatka Peninsula in Russia. (Photos by Denis Budkov/Caters News)

This is a portion of the first color 360-degree panorama from NASA's Curiosity rover, made up of thumbnails, which are small copies of higher-resolution images. The mission's destination, a mountain at the center of Gale Crater called Mount Sharp, can be seen in the distance, to the left, beginning to rise up. The mountain's summit will be imaged later. (Photo by NASA/JPL-Caltech/MSSS)

Francisca Gomez stands at an entrance to her home, a cave where she has been living for the past 50 years, in the mountains on the outskirts of Chusmuy, Honduras April 21, 2015. The 75-year old widow receives help from neighbors and friends and she makes a little money by selling wood she collects, according to a local newspaper. (Photo by Jorge Cabrera/Reuters)

People, carry food and water, past a tractor stuck in mud, stones and debris that were piled in a flood in the mountain village of Sipkovica, just above the town of Tetovo, in northwestern Macedonia, on Tuesday, August 4, 2015. A small number of people including children have died in floods that erupted after an hour of heavy torrential rains and strong winds that hit Tetovo and northwestern region of Macedonia late on Monday. (Photo by Zoran Andonov/AP Photo)

Claire McGuire (C) smiles after winning the women's snowboard division of the Bikini & Board Shorts Downhill at Crystal Mountain, a ski resort near Enumclaw, Washington April 19, 2014. Skiers and snowboarders competed for a chance to win one of four season's passes. (Photo by David Ryder/Reuters)

Austrian alpine skiers (LtoR) Georg Streitberger, Klaus Kroell, Max Franz, Joachim Puchner, Romed Baumann pose in the Olympic Rings on February 4, 2014 at the Mountain Olympic Village at the Rosa Khutor Alpine centre, four days prior to the start of the 2014 Sochi Winter Olympic Games. (Photo by Fabrice Coffrini/AFP Photo)