Klaus Littmann's FOR FOREST: The Unending Attraction of Nature in Wörthersee Stadion, Klagenfurt, Austria (© UNIMO)

Adélie penguins at Possession Island, Antarctica (© Tui De Roy/Minden Pictures)

Loch Lomond and The Trossachs National Park in autumn, Scotland (© Jon Arnold/Danita Delimont)

Sequence of enhanced-colour images of Jupiter (© Enhanced Image by Gerald Eichstädt and Sean Doran, CC BY-NC-SA, based on images provided Courtesy of NASA/JPL-Caltech/SwRI/MSSS)

Tintern Abbey, Monmouthshire, Wales (© Lynda Morris Photography/Getty Images)

Aerial view of Marlborough Sounds, New Zealand (© Mathias Ortmann/Getty Images)

Cleveland Clinic Lou Ruvo Centre for Brain Health in Las Vegas, Nevada, USA (© Garry Belinsky/Offset)

Octopus spotted during a night dive near Kona, Hawaii, USA (© Jeff Milisen/Alamy)

Letchworth State Park, New York, USA (© Jay O'Brien/Danita Delimont)

Bubble Nebula (NGC 7635) (© NASA, ESA, and the Hubble Heritage Team STScI/AURA)

Arches National Park, Moab, Utah, USA (© Whit Richardson/Alamy Stock Photo)

Boats massing for the Barcolana Regatta in the Gulf of Trieste, Italy (© Ababsolutum/E+/Getty Images)

A fossilised carboniferous fern (© Juan Carlos Munoz/Minden Pictures)

Misty sunrise in Ashdown Forest, East Sussex (© Tim Stocker Photography/Getty Images)

Close-up of a dragonfly wing (© Azwar Thaufeeq/500px/Getty Images)

Highbush blueberry plants in Acadia National Park, Maine, USA (© Danita Delimont/Gallo Images/Getty Images Plus)

Autumn leaves and goldfish in Tokyo, Japan (© qrsk/Moment/Getty Images)

Chimney Rock and Uncompahgre National Forest, Colorado, USA (© Cory Marshall/Tandem Stills + Motion)

Aerial view of a pumpkin patch in Half Moon Bay, California, USA (© Tinker Street/Michael O'Neal/Gallery Stock)

Pale-throated sloth perched in a tree on Sloth Island, Essequibo River, Guyana (© Suzi Eszterhas/Minden Pictures)

Colony of Common Mussels (Mytilus edulis) growing on striated rock formation exposed at low tide. Cornwall, England. (© Alex Hyde/Minden Pictures)

Blackbird eating a crab apple in a garden in Wiltshire (© Nick Upton/Minden Pictures)

A polar bear family near the Hudson Bay in Churchill, Manitoba, Canada (© Marco Pozzi Photographer/Getty Images)

County Bridge in New Hampshire, USA (© Denis Tangney Jr/E+/Getty Images)

Ring-tailed lemurs in Madagascar for World Lemur Day (© Image Source/Alamy)

Workers cleaning the clock face of Big Ben, London (© Reuters)

Palmenflughunde im Kasanka-Nationalpark, Sambia (© Nick Garbutt/Minden Pictures)

Straw-coloured fruit bats in Kasanka National Park, Zambia (© Nick Garbutt/Minden Pictures)

Charles Bridge over the Vltava River in Prague (© Martin Moxter/Offset)

一只坐在白杨树上的大雕鸮，阿尔伯塔 (© Ambre Haller/Getty Images)