National Theater, Cluj-Napoca, Romania (© Thomas Mueller/Shutterstock)

Bridalveil Fall, Yosemite National Park, California (© Jeff Foott/Minden Pictures)

Negratín Reservoir, Granada, Spain (© Andres Martinez Olmedo/Getty Images)

Killer whales in the waters off Spildra, Norway (© Alex Mustard/Minden Pictures)

Road to Mount Pico, Portugal (© Marco Bottigelli/Getty Images)

Cherry trees in full bloom near the Imperial Palace with Tokyo Tower in the background, Tokyo, Japan (© Jon Arnold/Danita Delimont)

Icelandic horses standing in a field, Iceland (© Rodrigo Lourezini/Shutterstock)

Cabins in Valley Forge National Historic Site, Pennsylvania (© Mark C. Morris/Shutterstock)

Cibeles Fountain and Madrid City Hall lit for International Women's Day, Madrid, Spain (© dpa picture alliance/Alamy)

Rainbow over Waimea Canyon and Waipo'o Falls, Kauai, Hawaii (© Beverley Van Praagh/Getty Images)

Edale Valley, Peak District, England (© John Finney/Getty Images)

Marshland, Gloucester, Massachusetts (© Thomas H. Mitchell/Getty Images)

Flags of the Commonwealth of Nations (© hamzehsh12/iStock/Getty Images Plus)

Labyrinth in Cyherbia Botanical Park, Cyprus (© Tpopova/Getty Images)

Agüero, Spain (© Andrea Comi/Getty Images)

Giant panda at Chengdu Panda Base, China (© Jim Zuckerman/Jaynes Gallery/DanitaDelimont)

Ballyvooney Cove, Copper Coast Geopark, Ireland (© Andrea Pistolesi/Getty Images)

Gamboa Crater, Mars (© NASA/JPL-Caltech/University of Arizona)

Aurora Borealis at Two Jack Lake, Alberta, Canada (© Jesús M. García/Getty Images)

Crocus flowers (© Raimund Linke/Getty Images)

Colorful pastel chalk (© Stephen Shepherd/plainpicture)

Lake Powell on the Colorado River, USA (© Peter Schaefer/Alamy)

Lenticular clouds, Patagonia (© Sasha Juliard/Shutterstock)

Blooming wild garlic, Hainich National Park, Germany (© Frank Sommariva/Getty Images)

Cecil Brewer Staircase, the Heal's Building, London, England (© Yiran An/Getty Images)

Wildflowers in Anza-Borrego Desert State Park, California (© Ron and Patty Thomas/Getty Images)

New York City skyline in fog (© Orbon Alija/Getty Images)

Milky Way above Tre Cime di Lavaredo, South Tyrol, Italy (© Juan Romero/Cavan Images)

Manatees, Crystal River, Florida (© Gregory Sweeney/Getty Images)

Peacock feathers (© Sarayut Thaneerat/Getty Images)

Steyr River, Austria (© guenterguni/Getty Images)