Men work at a makeshift oil refinery site in Marchmarin town, southern countryside of Idlib, Syria December 16, 2015. The refinery site, owned by Yousef Ayoub, 34, has been active for 4 months. Ayoub says that he gets the crude oil from Islamic State-controlled areas in Deir al-Zor province and Iraq. The price for a barrel of crude oil varies and is controlled by the Islamic State, but it is currently at $44 dollars per barrel, he said. (Photo by Khalil Ashawi/Reuters)

A visitor looks down from a terrace at a Volkswagen Beetle owners' meeting in Sao Bernardo do Campo January 25, 2015. Around 1000 Volkswagen Beetle cars took part in this event as part of celebrations marking Brazil's annual National Volkswagen Beetle day, which falls on January 20. (Photo by Paulo Whitaker/Reuters)

Artist Rachel Stubbs works on the final touches of a sand sculpture she has built as part of this year's “Once Upon a Time” themed annual Weston-super-Mare Sand Sculpture festival on April 16, 2014 in Weston-Super-Mare, England. Due to open on Good Friday, a team of award winning sand sculptors from across the globe have been working to create sand sculptures influenced by fairy tales and fables but that also include some current television and cinema blockbuster hits such as The Hunger Games, Game of Thrones and The Hobbit. (Photo by Matt Cardy/Getty Images)

Corey Arnold is a fine art photographer and a commercial fisherman, working the stormy waters of the Bering Sea by Alaska. His latest work documents life in this remote wilderness, both at sea and on the shore, capturing trawlers, foxes, eagles and the grandeur of the scenery. “Aleutian Dreams” can be seen at Charles A Hartman Fine Art in Portland, Oregon, until 27 May. Here: “Roadside Friend”. (Photo by Corey Arnold/Charles A. Harman Fine Art/The Guardian)

Pilots plan a flight manoeuvre with model aircraft at a military air base in Vasylkiv, Ukraine, August 3, 2016. (Photo by Gleb Garanich/Reuters)

Revelers take a selfie during a Holi Festival in Madrid, Spain, Sunday, April 26, 2015. The festival is based on the Hindu spring festival Holi, also known as the festival of colours where participants colour each other with dry powder and coloured water. (Photo by Andres Kudacki/AP Photo)

A man paddles a makeshift boat along a flooded street in Guasdualito, in the state of Apure, Venezuela, July 4, 2015. A total of 9,000 families have been affected by the overflowing of rivers Arauca and Sarare in Guasdualito, Apure state, because of the heavy rains in recent days in this area of the country, local media reported. (Photo by Carlos Eduardo Ramirez/Reuters)

Shell, which is the replica of the biggest detonated Soviet nuclear bomb AN-602 (Tsar-Bomb), is on display in Moscow, Russia, August 31, 2015. The shell is part of an exhibition organized by the state nuclear corporation Rosatom. (Photo by Maxim Zmeyev/Reuters)