Snow capped peak of Mount Cika viewed through hillside forest trees, near Dhermi, Albania, Europe

Kok-Moinok Canyon, a clay-sand structure formed on the slopes of arid mountains cut by water streams, Kyrgyzstan, Central Asia, Asia

Kimmeridge Bay, Jurassic Coast, UNESCO World Heritage Site, Dorset, England, United Kingdom, Europe

Castellana caves (Castellana Grotte), Apulia, Italy, Europe

Night-time, moonlit view of the geological formation known as 'Hole in the Wall along the wild coast in a region of South Africa's Eastern Cape Province formerly known as the Transkei. Stars can be seen in the sky.

Zodiacs cruising through the sea caves of Fugloy in the Faroe Islands

Egyptian temple of Debod, 2nd century BC, at dusk, Madrid, Spain, Europe

Saalfelder Feengrotten or Saalfeld Fairy Grottoes, Saalfeld, Thuringia, Germany, Europe

Mountain bikers in Love Valley, Guevercinlik Valley, Goereme, Cappadocia, Turkey

Mountain bikers cycling in Love Valley, Guevercinlik Valley, Goereme, Cappadocia, Turkey

Mountain bikers cycling in Goereme, Cappadocia, Turkey

Sink from the previous Maerjelensee, a glacier lake on the eastern edge of the Aletsch Glacier, Canton of Valais, Switzerland, Europe

Clouds float above the Painted Hills Unit of John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument. No grass grows on the Painted Hills Unit, Mitchell, Oregon, United States of America

Colourful layers of minerals are exposed at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America

Ireland, Stone Circle

The claystone hills are graceful and colourful at John Day Fossil Beds National Monument, Mitchell, Oregon, United States of America