Ancient Roman gold mining site of Las Médulas, León, Spain (© DEEPOL by plainpicture/David Santiago Garcia)

Deer in the grasslands at Jim Corbett National Park, Uttarakhand, India (© FLPA/Alamy Stock Photo)

Looking inland from Ponce de León Inlet toward the lighthouse, Florida (© Jason Sponseller/Shutterstock)

Rainbow at Victoria Falls in Zambia (© Dietmar Temps/Shutterstock)

Pronghorn buck (© Donald M. Jones/Minden Pictures)

Green tree frog and water lily, Lake Kissimmee, Florida (© Joanne Williams/Danita Delimont)

Cherry blossoms and Himeji Castle in Himeji, Japan (© Tororo/Getty Images)

The 2017 April full moon, or pink moon, rises over St. Michael's Mount, Cornwall, England (© Simon Maycock/Alamy Live News)

Aerial view of Santorini, Greece (© Amazing Aerial Agency/Offset)

A pod of narwhals near Baffin Island, Nunavut, Canada (© Eric Baccega/Minden Pictures)

Kermode bear cubs huddling in Canada's Great Bear Rainforest, British Columbia (© Ian McAllister/Offset)

Daffodils in Dora’s Field, Rydal, Lake District (© Simon Whaley Landscapes/Alamy Stock Photo)

Floating temples of Wat Chaloem Phra Kiat Phrachomklao Rachanusorn in Lampang Province, Thailand (© pa_YON/Getty Images)

Pantropical spotted dolphins off the coast of Ixtapa, Mexico (© Christian Vizl/Tandem Stills + Motion)

Bhagsu waterfall, Himachal Pradesh, India (© f9photos/iStock/Getty Images Plus)

Sipapu Bridge in Natural Bridges National Monument, Utah (© Fyletto/Getty Images)

Ruffed grouse in Algonquin Provincial Park, Ontario, Canada (© Jim Cumming/Getty Images)

Vernal Fall in Yosemite National Park, California (© elvistudio/Shutterstock)

Milky Way over Neist Point Lighthouse, Isle of Skye, Scotland (© Shaiith/Getty Images)

Bluebells in Micheldever Wood, Hampshire, England (© Hursley/Getty Images Plus)

The Grand Prismatic Spring in Yellowstone National Park, Wyoming (© Martin Rügner/DEEPOL by plainpicture)

Te Matua Ngahere, a giant kauri tree growing in Waipoua Forest, North Island, New Zealand (© Kim Westerskov/Getty Images)

Male king eider ducks swimming in Troms og Finnmark, Norway (© Pal Hermansen/Minden Pictures)

The Large Magellanic Cloud, photographed by the Hubble Space Telescope (© ESA/Hubble/NASA)

Southern rockhopper penguins in the Falkland Islands (© Heike Odermatt/Minden Pictures)

Sunset at Ruby Beach in Olympic National Park, Washington state (© Adam Mowery/Tandem Stills + Motion)

Aerial view of the marsh at Bourges, France (© Tuul & Bruno Morandi/Getty Images)

Rose Blanche Lighthouse, Newfoundland, Canada (© Adam Woodworth/Cavan)

A tractor kicks up dust while tilling fields on the Palouse near Pullman, Washington (© Ben Herndon/Tandem Stills + Motion)

Hoary redpoll nest in Lapland, Finland (© Maximilian Buzun/Alamy)