Seljalandsfoss waterfall, located in Iceland. Seljalandsfoss is one of the most famous waterfalls of Iceland. This waterfall of the river Seljalandsá drops 60 metres (200 ft) over the cliffs of the former coastline. It's possible to go behind the waterfall. (Photo by HotSpot Media)

Lorella Boccia attends Giffoni Film Festival blue carpet on July 23, 2014 in Giffoni Valle Piana, Italy. (Photo by Maria Laura Antonelli/AGF/SIPA Press)

An employee of a bakery talks on his mobile while balancing on his head a tray of freshly baked bread from a local bakery in a street in Cairo, Egypt, January 12, 2016. (Photo by Asmaa Waguih/Reuters)

A U.S. Army soldier with the 10th Special Forces Group and his military working dog jump off the ramp of a CH-47 Chinook helicopter from the 160th Special Operations Aviation Regiment during water training over the Gulf of Mexico as part of exercise Emerald Warrior 2011 on March 1, 2011. (Photo by Tech. Sgt. Manuel J. Martinez/U.S. Air Force)

In this Wednesday, July 20, 2016 photo, a child carries kettles through a flooded street with a woman in Tianjin, China. China says dozens of people have died or gone missing since Monday in massive floods across the country's north. (Photo by Chinatopix via AP Photo)

Crowds supporting the Same Sеx Marriage Survey listen to politicians and advocates at Taylor Square in the heart of Sydney's gay precinct on November 15, 2017 in Sydney, Australia. Australians have voted for marriage laws to be changed to allow same-sеx marriage, with the Yes vote claiming 61.6% to to 38.4% for No vote. Despite the Yes victory, the outcome of Australian Marriage Law Postal Survey is not binding, and the process to change current laws will move to the Australian Parliament in Canberra. (Photo by James Alcock/Getty Images)

Archive: A group of people dressed as Santa Claus wait for the bus on December 1960, London, England. (Photo by Keystone-France/Gamma-Keystone via Getty Images) Modern Day: Passengers wait for busses in Holborn on November 24, 2017 in London, England. (Photo by Chris J. Ratcliffe/Getty Images)

Revellers enjoy themselves during Hogmanay celebrations in Edinburgh, Scotland on December 31, 2017. (Photo by Russell Cheyne/Reuters)