A mountain hare hunkers down in a snowstorm, the Cairngorms, Scotland (© Lyle McCalmont/Getty Images)

The whirlpool in Myllykoski scenic area, Oulanka National Park, Kuusamo, Finland (© Lassi Rautiainen/Minden Pictures)

'Field of Light at Sensorio,' by Bruce Munro, Paso Robles, California (© George Rose/Getty Images)

Sperm whale mother and albino baby swimming off the coast of Portugal (© Flip Nicklin/Minden Pictures)

Burrowing parrots in Las Lajas, Argentina (© Cagan Hakki Sekercioglu/Getty Images)

Trakai Island Castle Museum in Trakai, Lithuania (© Andrius Aleksandravicius/Alamy)

Tianmen Mountain in Zhangjiajie, China (© Bogdan Dyiakonovych/Shutterstock)

Tianmen Mountain in Zhangjiajie, China (© Bogdan Dyiakonovych/Shutterstock)

Muir Woods National Monument near San Francisco, California (© Mia2you/Shutterstock)

Flags outside the UN's Palace of Nations in Geneva, Switzerland (© Mustafa Yalcin/Anadolu Agency/Getty Images)

Rakan statues at Daisho-in Temple, Miyajima, Japan (© Malcolm Fairman/Alamy)

Eibsee, a lake at the base of the Zugspitze, Bavaria, Germany (© Marc Hohenleitner/Huber/eStock Photo)

Mount Diablo State Park, California (© Yuval Helfman/Getty Images)

Male muskoxen near Prudhoe Bay in Alaska (© Oliver Smart/Alamy)

Aerial view of Boudhanath stupa in Kathmandu, Nepal (© Maksim Semin/Shutterstock)

Sunset in Val Gardena in the Dolomites of South Tyrol, Italy (© Marco Capellari/Getty Images)

A Brandt's cormorant hunts for a meal in a school of Pacific chub mackerel beneath an oil rig off the coast of Los Angeles, California (© Alex Mustard/Minden Pictures)

Backcountry adventurer Alex Peterson speed riding on the south side of Mount Hood, Oregon (© Richard Hallman/DEEPOL by plainpicture)

Eurasian red squirrel in the Cairngorms, Scottish Highlands, Scotland (© Images from BarbAnna/Getty Images)

Eurasian red squirrel in the Cairngorms, Highlands of Scotland (© Images from BarbAnna/Getty Images)

Northern lights near Whitehorse in Yukon, Canada (© Design Pics/Danita Delimont)

Zebras and wildebeests in the Serengeti National Park, Tanzania (© Raffi Maghdessian/Cavan Images)

Sunlit ridges against volcanic scree on Eyjafjallajökull, a volcano in Iceland (© Erlend Haarberg/Minden Pictures)

The Chinese New Year celebration in Xi'an, China (© Aleksandar Plavevski/Shutterstock)

The Taj Mahal in Agra for India's Republic Day (© Michele Falzone/plainpicture)

View of New York City from the International Space Station (© NASA Photo/Alamy)

Cape Disappointment Lighthouse in Ilwaco, Washington, for the formation of the modern US Coast Guard (© Tom Schwabel/Tandem Stills + Motion)

Semuc Champey, a nature park in Guatemala (© Joel Sharpe/Getty Images)

Aerial view of a car crossing over the frozen surface of Lake Baikal, Russia (© Amazing Aerial Agency/Offset)

A reddish egret hunts in Fort De Soto Park, Florida (© Brian Lasenby/Getty Images)