This photo of an elephant seal and Gentoo penguin shot by Andrew James in Yankee Harbour, Antarctica. (Photo by Andrew James/Travel Photographer of the Year)

Aerial photo taken on March 4, 2017 shows cole flower fields in Luoping County, southwest China's Yunnan Province. (Photo by Xinhua/Barcroft Images)

Photochromes are vibrant and nuanced prints hand-coloured from black-and-white negatives. Created using a process pioneered in the 1880s, these images offer a fascinating insight into the world when colour photography was still in its infancy. A Tour of the World in Photochromes is at the Swiss Camera Museum, Vevey, until 21 August. Here: Street food in the Strada del Porto in Naples, Italy, 1899. (Photo by Swiss Camera Museum/The Guardian)

The sun rises between Sgurr nan Gillean and Knight’s Peak, Black Cuillin, Isle of Skye. (Photo by Adrian Trendall/Mountain Photo of the Year)

On the western side of Mount Hood lies the longest glacier cave system in the contiguous United States. In 2012, these caves were mapped to a combined length of 7,166.8 feet by cave explorers Brent McGregor and Eddy Cartaya. Currently, the total passage length is hundreds of feet less. Glaciers are frozen rivers; they are always moving and changing... (Photo and caption by Josh Hydeman)

The bare feet of a devotee are pictured as she takes a dip at the Bagmati River during the “Bol Bom” (Say Shiva) pilgrimage in Kathmandu July 21, 2014. The faithful, chanting the name of Lord Shiva, run about 15 km (9 miles) barefooted toward Pashupatinath temple seeking good health, wealth and happiness. (Photo by Navesh Chitrakar/Reuters)

Wildlife photographer Danté Fenolio has headed into areas untouched by sunlight – deep seas, caves and underground – and found creatures that are exploding with colour. Here: The golden harlequin toad has vanished from the wild, and only a small number live on in captivity. A fungus caused them, and many other amphibians, to die out in their home in Central America. (Photo by Danté Fenolio/The Guardian/Johns Hopkins University Press)

Pamukkale, Turkey, is home to these terrace pools, formed by the build-up of carbonate mineral from the warm water flowing from the thermal springs above. (Photo by Image Courtesy of Jennifer Hayes/Getty Images)