Knuthöjdsmossen, a nature reserve in Sweden (© Sven Halling/DEEPOL/plainpicture)

Little Pigeon River, Great Smoky Mountains National Park, Tennessee (© GreenStock/Getty Images)

Miravet on the Ebro River, Tarragona, Catalonia, Spain (© Eloi_Omella/Getty Images)

Sea otter floating in a kelp bed in Alaska Maritime National Wildlife Refuge (© Gerry Ellis/Minden Pictures)

Mona Vale Rockpool, Sydney, Australia (© jamenpercy/Getty Images)

Arlington National Cemetery in Virginia (© Dennis Govoni/Getty Images)

Butchart Gardens in Brentwood Bay, British Columbia, Canada (© 2009fotofriends/Shutterstock)

Jotunheimen National Park in Norway (© Marisa Estivill/Shutterstock)

A Julia butterfly on the nose of a yellow-spotted river turtle, Amazon Region, Ecuador (© Westend61/Getty Images)

Baobab trees at sunset, Avenue of the Baobabs, Madagascar (© Framalicious/Shutterstock)

Tea garden at Yangjiatang Village, Songyang County, China (© feng xu/Getty Images)

Honey bee on lavender flowers (© Anthony Brown/Alamy)

Mount Hamilton, near San Jose, California (© Jeffrey Lewis/TANDEM Stills + Motion)

'The Spirit of Electricity' by Raoul Dufy, Museum of Modern Art, Paris, France (© BERTRAND GUAY/AFP via Getty Images)

A delta in the Venetian Lagoon, Italy (© Dimitri Weber/Amazing Aerial Agency)

Great green macaw, Mexico (© Ondrej Prosicky/Shutterstock)

Big Ben and the Palace of Westminster, London, England (© Puthipong Worasaran/Getty Images)

Porto Flavia, Sardinia, Italy (© Francesco Riccardo Iacomino/Getty Images)

Torres del Paine National Park, Patagonia, Chile (© Marco Bottigelli/Getty Images)

An iris garden in Tokyo, Japan (© M.Arai/Getty Images)

Leopard mother grooming her cub, Jao Reserve, Botswana (© Suzi Eszterhas/Minden Pictures)

Minnesota State Capitol, St. Paul, Minnesota (© lavin photography/Getty Images)

Common chameleon (© Photostock-Israel/SPL/Getty Images)

Donkeys in a valley near Rhyolite, Nevada (© Moelyn Photos/Getty Images)

Dunluce Castle, County Antrim, Northern Ireland (© DieterMeyrl/Getty Images)

An ultralight aircraft flying over the sands of Namibia (© Burt Johnson/Alamy)

Paper flags strung over a street in San Miguel de Allende, Mexico (© William Zinn/Getty Images)

Plaza de España, Seville, Spain (© Horia Merla/Getty Images)

The Milky Way framed by Double Arch in Arches National Park, Utah (© Adventure_Photo/Getty Images)

Striated heron on a Victoria water lily, Pantanal, Brazil (© Gerald Corsi/Getty Images)

Plumeria flowers, Hawaii (© Miranda Jans/Getty Images)