Mount Etna erupting in 2013, Sicily, Italy (© Wead/Alamy Live News)

A blue tit amongst daffodils on St David's Day in Blaenpennal, Aberystwyth Wales, U.K. (© Philip Jones/Alamy Stock Photo)

Volcano Llaima with Araucaria trees in the foreground, Conguillío National Park, Chile (© Fotografías Jorge León Cabello/Getty Images)

Two female lions in the forest surrounding Lake Nakuru, Kenya (© Scott Davis/Tandem Stills + Motion)

Aerial image of Mount Logan rising above the clouds in Kluane National Park, Yukon (© plainpicture/Design Pics/Robert Postma)

Mineral-laden water in the Rio Tinto in Minas de Rio Tinto mining area, Huelva province, Andalusia, Spain (© David Santiago Garcia/Getty Images)

Komodo National Park, Labuan Bajo, Flores, Indonesia (© Thrithot/Adobe Stock)

Great blue herons in the Wakodahatchee Wetlands, Delray Beach, Florida (© Marie Hickman/Getty Images)

Frida Kahlo mural, Mexico (© Jessica Sample/Gallery Stock)

Foothills of the Diablo Range near San Jose, California (© Jeff Lewis/Tandem Stills + Motion)

Snow and ice along the shoreline of Lake Superior in winter; Thunder Bay, Ontario (© plainpicture/Design Pics/Susan Dykstra)

Thor's Well at Cape Perpetua on the Oregon coast (© Cavan Images/Offset by Shutterstock)

A balloon flies over the Pyramid of the Sun at sunrise in Teotihuacan, Mexico (© Marco Ugarte/AP Photo)

Spring ice along the shore of Lake Winnipeg, Manitoba (© Mike Grandmaison/Jaynes Gallery/DanitaDelimont.com)

Lyon astronomical clock, Lyon, France (© kyolshin/Alamy)

Screech owl resting in a tree cavity, Massapequa Preserve, Long Island, New York (© Vicki Jauron, Babylon and Beyond Photography/Getty Images)

Giant panda cub in Bifengxia Panda Base, Sichuan, China (© Suzi Eszterhas/Minden Pictures)

Inisheer, the smallest of the three Aran Islands in Galway Bay, Ireland (© Chris Hill/Minden Pictures)

View of Tofino Bay, Vancouver, B.C. (© Ben Kotenberg/Shutterstock)

Aerial view of the 'City of Adelaide' shipwreck with trees growing on it, Magnetic Island, Queensland, Australia (© Amazing Aerial Agency/Offset by Shutterstock)

Sundial on Parnidis Dune, Curonian Spit, in Lithuania (© amoklv/Getty Images)

Bluebell flowers carpet the Hallerbos forest floor, Flanders, Belgium (© Jason Langley/plainpicture)

Satellite image of the Mania River in Madagascar (© NASA Earth Observatory image by Joshua Stevens, using Landsat data from the US Geological Survey)

Humpback whale mother pushes her sleeping calf to surface, Maui, Hawaii (© Ralph Pace/Minden Pictures)

Common rhododendrons in Semper Forest Park, Ruegen, Germany (© Sandra Bartocha/Minden Pictures)

Cradle Mountain-Lake St. Clair National Park, Tasmania, Australia (© Paparwin Tanupatarachai/Getty Images)

Mountain hare running across snow-covered upland, Scotland (© SCOTLAND: The Big Picture/Minden Pictures)

Lightning striking over 70 Mile Butte and Sleeping Lion Butte, Grasslands National Park, Saskatchewan (© Design Pics/DanitaDelimont.com)

The basalt rock formations of Reynisdrangar on Reynisfjara Beach, Iceland (© Cavan Images/Getty Images)

A close-up of bunchberry in Rose Blanche, Newfoundland (© Mike Grandmaison/Jaynes Gallery/DanitaDelimont.com)

Wayag Island at Raja Ampat, Indonesia (© Amazing Aerial Agency/Offset by Shutterstock)