Barrier reef off the island of Grande Terre in the French overseas territory of New Caledonia (© Karsten Wrobel/Getty Images)

Skipper butterfly on a coneflower, Rockefeller State Park Preserve, New York (© Marianne A. Campolongo/Alamy)

Bicycles on a bridge in Utrecht, Netherlands (© George Pachantouris/Getty Images)

The beach at Cala Luna, Sardinia, Italy (© guenterguni/Getty Images)

Bottle-cap mural made by Oscar Olivares in Guatire, Venezuela (© FEDERICO PARRA/AFP via Getty Images)

Summit of Pine Mountain, Angeles National Forest, California (© Matthew Kuhns/TANDEM Stills + Motion)

Steller sea lions, Vancouver Island, British Columbia, Canada (© Steve Woods Photography/Getty Images)

Old City of Dubrovnik in Dalmatia, Croatia (© bluejayphoto/Getty Images)

Aerial view of Everglades National Park, Florida (© Robert DelVecchio - OcuDrone/Getty Images)

Greater flamingos, Lüderitz, Namibia (© Karine Aigner/TANDEM Stills + Motion)

Chisos Mountains, Big Bend National Park, Texas (© Dean Fikar/Getty Images)

Vila Franca Islet, São Miguel Island, Azores, Portugal (© ARoxo/Getty Images)

Flag display at the US Capitol, Washington, DC (© kmiragaya/Adobe Stock)

Lesser rhea adult male with chicks, Torres del Paine National Park, Patagonia, Chile (© Ignacio Yufera/Minden Pictures)

Sea turtle, Fernando de Noronha, Brazil (© João Vianna/Getty Images)

Maritime forest in Cumberland Island National Seashore, Georgia (© Chris Moore/TANDEM Stills + Motion)

Asian swallowtail butterfly on a red spider lily (© lzh/Getty Images)

Texas State Capitol in Austin (© joe daniel price/Getty Images)

Seljalandsfoss waterfall at sunset, Iceland (© Tom Mackie/AWL/plainpicture)

Masai giraffe mother grooming her calf in the Serengeti, Tanzania (© Alberto Cassani/Getty Images)

Amazon rainforest, Ecuador (© Mark Fox/Getty Images)

The Elbe in Dresden, Germany (© Sean Pavone/Getty Images)

Delicate Arch, Arches National Park, Utah (© mmac72/Getty Images)

St. Michael's Church Tower on Glastonbury Tor, Glastonbury, Somerset, England (© Gavin Hellier/Getty Images)

The Milky Way over Horse Head Rock, New South Wales, Australia (© Philip Thurston/Getty Images)

Splendid leaf frog (© Jan Stria/Shutterstock)

Rainbow flags at New York Pride (© Alan Schein/Getty Images)

Blue lagoon at Pulau Ay, Banda Islands, Indonesia (© fabio lamanna/Alamy)

Wolfe Creek Crater, Australia (© Abstract Aerial Art/Getty Images)