Gray seal pup resting on a beach in Blakeney National Nature Reserve, England (© Kevin Sawford/Getty Images)

Aerial view of the theatre at the ancient city of Hierapolis, near Pamukkale, Turkey (© Amazing Aerial Agency/Offset by Shutterstock)

Cape foxes in the Kalahari Desert in South Africa (© NSP-RF/Alamy)

Wildflowers in Kettle River Recreation Area, British Columbia, Canada (© Debra Brash/plainpicture)

Great Point Light on Nantucket Island, Massachusetts, USA (© Cate Brown/Cavan Images)

Tolbachik volcanic complex on the Kamchatka Peninsula, Russia (© Egor Vlasov/Shutterstock)

Enhanced-colour composite of the Caloris Basin, Mercury (© Nasa/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

Grey seal pup resting on a beach in Blakeney National Nature Reserve, Norfolk (© Kevin Sawford/Getty Images)

The bell tower in Lake Reschen in South Tyrol, Italy (© Scacciamosche/Getty Images)

Bàu Cá Cái mangrove forest in Quảng Ngãi Province, Vietnam (© Robert Harding World Imagery/Offset)

Water ripples on the surface of Ežezers Lake in the Latgale region, Latvia (© Eaglewood Films/Nimia)

Boats in Tollesbury Marina, Essex (© Geoffrey Robinson/Alamy Stock Photo)

The Panthéon in Paris, France (© manjik/Shutterstock)

The flooded crypt at Winchester Cathedral, Hampshire (© Oliver Hoffmann/Alamy)

Small tortoiseshell butterfly feeding on flower nectar, Lower Saxony, Germany (© Duncan Usher/Minden Pictures)

North Pacific humpback whale breaching in Frederick Sound, Alaska (© Tony Wu/Minden Pictures)

Nine-spotted moth in Switzerland (© Thomas Marent/Minden Pictures)

The Grand Canal and Basilica di Santa Maria della Salute in Venice, Italy (© Jim Richardson/Offset by Shutterstock)

The Earth rises over Mare Smythii on the Moon (© Image Science and Analysis Laboratory, NASA-Johnson Space Center)

Dinant and the River Meuse in Namur, Belgium (© Kadagan/Shutterstock)

The town of Dinant and the River Meuse in Namur province, Belgium (© Kadagan/Shutterstock)

Wooden doors and a stone path at the base of Fort Lovrijenac in Kolorina Bay, Dubrovnik (© Barbara Vallance/Getty Images)

The Giant's Causeway, Bushmills, County Antrim (© Chiara Salvadori/Getty Images)

Elephants at Kapama Private Game Reserve in South Africa (© Simon Eeman/Getty Images)

Hamelin Pool Marine Nature Reserve, Shark Bay, Australia (© Abstract Aerial Art/Getty Images)

Tamul waterfall in San Luis Potosí, Mexico (© Robert Harding World Imagery/Offset by Shutterstock)

Northern gannet (Morus bassanus) in flight, Troupe Head RSPB Reserve, Aberdeenshire (© Dave Pressland/Minden Pictures)

Kalsoy Island, part of the Faroe Islands (© Swen Stroop/Getty Images Plus)

站在河马身上的锤头鹳，津巴布韦马纳潭国家公园 (© David Fettes/Getty Images)

Hot air balloons over Clifton Suspension Bridge at sunrise, Bristol (© Rich Jones Photography/Getty Images)

A lava flow hits water to create an explosion as a tourist boat passes, Hawaii Volcanoes National Park, USA (© Patrick Kelley/Getty Images)