In this August 1, 2014 photo provided by the National Park Service are male caribou antlers in the Oolah Valley, likely the result of a grizzly kill as he migrated south for the winter at the Arctic National Park and Preserve in Alaska. The nation's northernmost national park says its new management plan will have to consider the effects of a new industrial road to the mining district of Ambler, the first road that would be constructed within its Maryland-sized boundaries. (Photo by Cadence Cook/AP Photo/National Park Service)

A man lies on the floor during a ritual at the Sorte Mountain on the outskirts of Chivacoa, in the state of Yaracuy, Venezuela October 10, 2015. One long night every year in a mountainous rainforest in Venezuela, hundreds gather to dance on red-hot embers, enter trance-like states, and worship an ancient goddess known as Maria Lionza. Those who travel to the mountain known as Sorte in central Venezuela are practitioners of a cult that is built on local indigenous traditions. (Photo by Marco Bello/Reuters)

Tianmen Mountain is a mountain located within Tianmen Mountain National Park, Zhangjiajie, in northwestern Hunan Province, China.

Ray Collins is a colorblind Australian coal miner who is in love with the ocean. He spends his off days photographing it. Collins says he enjoys capturing the moment before the moment, the anticipation, not knowing how the end of the wave's journey will play out. (Photo by Ray Collins)

In this May 24, 2016 photo, a young boy descends the Qullqip'unqu mountain looking out at the tens of thousands of pilgrims gathered to celebrate the three-day festival Qoyllur Rit’i, translated from the Quechua language as Snow Star, in the Andean Sinakara Valley, in Peru's Cusco region. The celebration that mixes Catholic and indigenous beliefs honors Jesus as well as the area’s glacier, which is considered sacred among some indigenous people. While the native celebration is far older, the Christian part of the ritual stretches back to the 1700s, when Jesus is said to have appeared to a young shepherd in the form of another boy. (Photo by Rodrigo Abd/AP Photo)

Most pet cats will become timid or defensive when outdoors, but not Millie – after being adopted by her mountain-climbing owner Craig Armstrong, Millie has become a feline hiking and mountain-climbing legend.

The sun rises between Sgurr nan Gillean and Knight’s Peak, Black Cuillin, Isle of Skye. (Photo by Adrian Trendall/Mountain Photo of the Year)