Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province June 30, 2014. The fighters held the parade to celebrate their declaration of an Islamic “caliphate” after the group captured territory in neighbouring Iraq, a monitoring service said. The Islamic State, an al Qaeda offshoot previously known as Islamic State in Iraq and the Levant (ISIL), posted pictures online on Sunday of people waving black flags from cars and holding guns in the air, the SITE monitoring service said. (Photo by Reuters/Stringer)

Armed man stand at entrance of the naval headquarters in Sevastopol, March 19, 2014. Around a dozen Ukrainian servicemen, unarmed and in civilian clothes, walked out of the Ukrainian naval headquarters in the Crimean port of Sevastopol on Wednesday after it was taken over by pro-Russian forces, a Reuters witness said. (Photo by Baz Ratner/Reuters)

Promotional models use their smartphones during their break at the Global Mobile Internet Conference in Beijing May 6, 2014. Mobile Internet industry executives, developers and investors from more than 30 countries took part in the Global Mobile Internet Conference in Beijing, the organiser said. (Photo by Kim Kyung-Hoon/Reuters)

A woman holds a rooster burned during a fire on a hill, where more than 100 homes were burned due to a forest fire but there have been no reports of death, local authorities said in Valparaiso, Chile January 2, 2017. (Photo by Rodrigo Garrido/Reuters)

Afghan firefighters spray water on a U.S. armoured vehicle after a suicide attack on the outskirts of Jalalabad, January 5, 2015. A suicide attacker targeted a U.S. convoy on the outskirts of Jalalabad on Monday but so far no causalities have been reported yet, provincial spokesman Ahmadzia Abdulzai said. (Photo by Reuters/Parwiz)

A colourful sky before sunrise on Whitley Bay beach on December 21, 2015, as December could be the mildest across a large part of England since records began more than 350 years ago, forecasters have said. (Photo by Owen Humphreys/PA Wire)

Underwater photographer of the year – winner. Dancing Octopus by Gabriel Barathieu (France). Location: Island of Mayotte, off the coast of south-east Africa. “Balletic and malevolent”, one judge said of this octopus, hunting in a lagoon. Barathieu waited until spring tides when there was just 30cm of water on the flats and plenty of light in the shallows. (Photo by Gabriel Barathieu/UPY2017)

An incredible moon rise behind the World Trade Center, Manhattan, New York on August 23, 2016. The breath-taking photo was taken by photographer Jennifer Khordi. She said: it was just absolutely amazing to see this. (Photo by Jennifer Khordi/Caters News Agency)