Gamboa Crater, Mars (© NASA/JPL-Caltech/University of Arizona)

The Holsten Gate in Lübeck, Germany (© Harald Nachtmann/Getty Images)

Lake Negratin, Granada, Spain (© Andres Martinez Olmedo/Getty Images)

Killer whales in Spildra, Norway (© Alex Mustard/Minden Pictures)

Road to Mount Pico, Portugal (© Marco Bottigelli/Getty Images)

Cherry trees in full bloom near the Imperial Palace with Tokyo Tower in the background, Tokyo, Japan (© Jon Arnold/Danita Delimont)

Icelandic horses standing in a field, Iceland (© Rodrigo Lourezini/Shutterstock)

Aerial view of terraced rice fields, Yuanyang, China (© AlexGcs/Getty Images)

Aurora display, Whitehorse, Yukon, Canada (© John Hyde/plainpicture/Design Pics)

Rainbow over Waimea Canyon and Waipo'o Falls, Kauai, Hawaii, USA (© Beverley Van Praagh/Getty Images)

Edale Valley, Peak District, UK (© John Finney/Getty Images)

Marshland, Gloucester, Massachusetts (© Thomas H. Mitchell/Getty Images)

Sheep in South Downs National Park, East Sussex, England (© Slawek Staszczuk/Alamy)

Lionesses sleeping, Serengeti National Park, Tanzania (© Cavan Images/Shutterstock)

Cyherbia Botanical Park, Cyprus (© Tpopova/Getty Images)

Agüero, Spain (© Andrea Comi/Getty Images)

Chengdu Panda Base, China (© Jim Zuckerman/Jaynes Gallery/DanitaDelimont)

Ballyvooney Cove, Copper Coast Geopark, Ireland (© Andrea Pistolesi/Getty Images)

Barn owl, England (© Ondrej Prosicky/Getty Images)

Purple crocus (© Raimund Linke/Getty Images)

Colourful pastel chalk (© Stephen Shepherd/Plainpicture)

Lake Powell, USA (© Peter Schaefer/Alamy)

Gorges du Fier, Haute-Savoie, France (© Jean-Philippe Delobelle/Biosphoto/Alamy)

Blooming wild garlic, Hainich National Park, Germany (© Frank Sommariva/Getty Images)

Cecil Brewer Staircase, London, England (© Yiran An/Getty Images)

Wildflowers in Anza Borrego Desert State Park, California, USA (© Ron and Patty Thomas/Getty Images)

New York City skyline in the clouds (© Orbon Alija/Getty Images)

Milky Way above Tre Cime di Lavaredo, Italy (© Juan Romero/Cavan Images)

Two manatees, Crystal River, Florida, USA (© Gregory Sweeney/Getty Images)

Peacock feathers (© sarayut Thaneerat/Getty Images)

Steyr river, Austria (© guenterguni/Getty Images)