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

Parliament Building in Ottawa at sunset (© Serega/Getty Images)

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

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

Boreal forest at Trans-Taiga Road region in Northern Quebec (© Posnov/Getty Images)

Great Point Light on Nantucket Island, Massachusetts (© 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, England (© Kevin Sawford/Getty Images)

American Basin in southern Colorado's San Juan Mountains (© Blaine Harrington III/Alamy)

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)

Adult female Grizzly Bear (Ursus arctos horribilis) and cub feeding on sedges in Great Bear Rainforest, B.C. (© Jack Chapman/Minden Pictures)

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

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

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

Happy hot air balloon (© Leonsbox/Getty Images Plus)

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)

Earthrise across Mare Smythii on the moon (© Image Science and Analysis Laboratory, NASA-Johnson Space Center)

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

Blue wildebeest herd migrating at sunset, Maasai Mara Game Reserve, Kenya (© Denis-Huot/Minden Pictures)

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

Disko Bay, Ilulissat, Greenland (© Kertu/Shutterstock)

Glacial turquoise water of Kicking Horse River, Yoho National Park, B.C. (© Oleg Charykov/Getty Imgaes)

The Allen Lambert Galleria in Brookfield Place, Toronto (© AWL Images/DanitaDelimont)

Hamelin Pool Marine Nature Reserve in Australia (© Abstract Aerial Art/Getty Images)

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

Hamerkop standing on a hippo, Mana Pools National Park, Zimbabwe (© David Fettes/Getty Images)

A pathway through the dense woodland forest at Golden Ears Provincial Park, B.C. (© SibsUK/Shutterstock)