National Geographic has created “Air, Land & Sea: the 50 greatest wildlife photographs” exhibition. Here: CT4 Crocodile cave on the Salamat river. Set up with Nathan Williamson last chip rain came while we were with the nomads. (Photo by Michael Nichols/National Geographic)

Gifts for the homeless are handed out during Santa Bar Crawl, Oxford, England on December 5, 2017. Here: Oxford university students on a Santa-themed pub crawl. (Photo by Greg Blatchford/Rex Features/Shutterstock)

A boy bursts a soap-bubble at Gorky Park in Moscow on July 19, 2017. (Photo by Mladen Antonov/AFP Photo)

Clouds gather as walkers pause atop a ridge in Mountain View, California January 7, 2016. (Photo by Noah Berger/Reuters)

Hotel staff practice self-defence skills after a training session given by team member of Special Weapons and Tactics (SWAT) team, in Hangzhou, Zhejiang province, April 7, 2016. (Photo by Reuters/Stringer)

“The Giant's Causeway is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located in County Antrim on the northeast coast of Northern Ireland, about three miles (4.8 km) northeast of the town of Bushmills. It was declared a World Heritage Site by UNESCO in 1986, and a National Nature Reserve in 1987 by the Department of the Environment for Northern Ireland”. – Wikipedia

Photo: Visitors walk on the Giant's Causway on March 14, 2012 in Portrush, Northern Ireland. (Photo by Peter Macdiarmid/Getty Images)