Replica of the Wright Flyer undergoing aerodynamic tests at NASA's Langley Research Center, Virginia (© Chuck Thomas/Science Photo Library)

Hawaii Volcanoes National Park, Hawaii (© Grant Ordelheide/Tandem Stills + Motion)

Aerial view of the Washington Monument in Washington, DC (© NASA Photo/Alamy)

A humpback whale off the coast of Maui in Hawaii (© Design Pics/Danita Delimont)

Swift fox pups in Grasslands National Park near Val Marie in Saskatchewan, Canada (© John E Marriott/age fotostock)

White storks at Los Barruecos Natural Monument, Caceres, Spain (© Wild Wonders of Europe/Widstrand/Minden Pictures)

White storks at Los Barruecos Natural Monument, Cáceres, Spain (© Wild Wonders of Europe/Widstrand/Minden Pictures)

Cape Neddick Light in York, Maine (© Haizhan Zheng/Getty Images)

Male leopard in Linyanti Wildlife Reserve, Botswana (© Karine Aigner/Tandem Stills + Motion)

The Supertree Grove in Singapore's Gardens by the Bay (© John Warburton-Lee/Danita Delimont)

Seville, Spain’s Guadalquivir River and Triana Bridge for the 500th anniversary of Magellan’s departure (© Zu Sanchez Photography/Getty Images)

Elephants in the Amboseli National Park, Kenya (© Adam Bannister/Offset)

Elephants in Amboseli National Park, Kenya (© Adam Bannister/Offset)

Mars Express image of the icy cap at Mars’ south pole (© ESA/DLR/FU Berlin/Bill Dunford)

Male and female Ecuadorian horned anoles in Mindo, Ecuador (© James Christensen/Minden Pictures)

Smögen, Sweden (© Martin Wahlborg/Getty Images Plus)

Yukon River viewed from the Midnight Dome, Dawson City, Yukon, Canada (© Robert Postma/Getty Images)

Bees for National Honey Bee Day (© Angela Parker/Offset)

Tidal pools of Leça da Palmeira, Portugal (© Fernando Guerra/age fotostock)

Muje-Oulu Lake in eastern Finland (© Topi Ylä-Mononen/plainpicture)

Wildebeest herd crossing the Mara River between Kenya and Tanzania (© zhengvision/Getty Images)

｢朝顔｣ (© Aflo Co. Ltd./Alamy Stock Photo)

Farmland in Washington state's Palouse region (© Art Wolfe/Getty Images)

Brown bears in Katmai National Park and Preserve, Alaska (© imageBROKER/SuperStock)

Satellite image of the Burning Man festival in Black Rock City, Nevada (© DigitalGlobe/ScapeWare3d/Getty Images)

Royal Albert Hall during the annual BBC Proms festival in London (© Oli Scarff/Getty Images)

Anak Krakatoa volcano erupting off the coast of Sumatra, Indonesia (© Martin Rietze/Alamy)

The Garden of the Palazzo Corsini al Prato in Florence, Italy, for the New Generation Festival (© Will Perrett/Alamy)

Blackpool Pier and Tower illuminations, England (© Premium/UIG/Getty Images)

Hardee County Fair in Wauchula, Florida (© Oscar G. Davila/Getty Images)

Slacklining between giant boulders in Bishop, California (© Evgeny Vasenev/Aurora Photos)