Barrier reef off Grande Terre, New Caledonia, France (© Karsten Wrobel/Getty Images)

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

Little Pigeon River, Great Smoky Mountains National Park, Tennessee, United States (© 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, United States (© Gerry Ellis/Minden Pictures)

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

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

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)

A bookshop in Hay-on-Wye, Wales, June 1997 (© Epics/Contributor/Hulton Archive/Getty Images)

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

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

Mount Hamilton, San Francisco Bay Area, California, United States (© 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 Parliament, Palace of Westminster, London, England (© Puthipong Worasaran/Getty Images)

Porto Flavia, Sulcis-Iglesiente, Sardinia, Italy (© Marco Bottigelli/Getty Images)

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

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

Yoho National Park, British Columbia, Canada (© Feng Wei Photography/Getty Images)

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

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

Donkeys in a valley near Rhyolite, Nevada, United States (© 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 Stock Photo)

Beach huts in Brighton and Hove, England (© Moonstone Images/iStock/Getty Images)

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

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

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