Seawater cascades over an ancient coral reef, Hang Rai, Vietnam (© Thang Tat Nguyen/Getty Images)

St Davids Cathedral, Pembrokeshire (© Michael Roberts/Moment/Getty Images)

Electric guitars and amplifiers (© Third Eye Images/The Image Bank/Getty Images)

Leopard in a tree, Kruger National Park, South Africa (© Tonino De Marco/Minden Pictures)

Arenal Volcano seen from Monteverde, Costa Rica (© Lukas Bischoff/Getty Images)

Traffic circle and highway in Bangkok, Thailand (© Avigator Fortuner/Shutterstock)

Wahclella Falls in the Columbia River Gorge, Oregon, USA (© Eric Vogt/Tandem Stills + Motion)

Roques de Benet, Els Ports Natural Park, Catalonia, Spain (© Sergi Boixader/Alamy Stock Photo)

Tate Modern lit up on International Women's Day, London (© Stephen Chung/Alamy Stock Photo)

Bisti/De-Na-Zin Wilderness, New Mexico, USA (© Ian Shive/Tandem Stills + Motion)

Mute swan mother and cygnet, Stanpit Marsh, England (© LecartPhotos/Alamy Stock Photo)

A sleeping koala, Australia (© Anton Rogozin/Getty Images)

Bryce Canyon National Park, Utah, USA (© Jim Patterson/Tandem Stills + Motion)

Lesser flamingos flying over Lake Magadi, Kenya (© Vicki Jauron, Babylon and Beyond Photography/Getty Images)

Wat Phra Ngam, Ayutthaya Historical Park, Thailand (© boonchai wedmakawand/Alamy Stock Photo)

Anza-Borrego Desert State Park, California, USA (© Stephen Matera/Tandem Stills + Motion)

Giant panda eating bamboo, Chengdu, China (© Suzi Eszterhas/Minden Pictures)

St. Finian's Bay, County Kerry, Ireland (© Atlantide Phototravel/Getty Images)

Elephant Rock, Al-Ula, Saudi Arabia (© Lubo Ivanko/Shutterstock)

Cave Dale and Peveril Castle in Castleton, Peak District National Park, Derbyshire, England (© James Osmond/Alamy)

Tree frog on leaf (© Tetsuya Tanooka/DEEPOL by plainpicture)

Bwindi Impenetrable National Forest, Uganda (© Art Wolfe/DanitaDelimont.com)

Blue Spring, Te Waihou Walkway, New Zealand (© Ian Beattie/Alamy)

Large anvil clouds above the Amazon in Brazil (© NASA)

Silvereyes on a cherry blossom branch, South Korea (© TigerSeo/Getty Images)

Hindu devotees play with colourful powders during Holi, India (© Avishek Das/SOPA Images/LightRocket via Getty Images)

The Teatro Colón in Buenos Aires, Argentina (© Wei Hao Ho/Alamy Stock Photo)

Cherry blossoms in Shanghai, China (© Yaorusheng/Getty Images)

South Stack Lighthouse, Holyhead, Wales (© mariotlr/Getty Images)

Brown-throated three-toed sloth sleeping in cecropia tree, Costa Rica (© Juan Carlos Vindas/Getty Images)

'Vanishing Point' by French street artist JR on the facade of Palazzo Farnese, Rome, Italy (© Fabrizio Troiani/Alamy)