A French riot police officer is surrounded by flames, during a demonstration against the controversial labour reforms of the French government in Paris on September 15, 2016. Opponents of France's controversial labour reforms took to the streets on September 15, 2016 for the 14th time in six months in a last-ditch bid to quash the measures that lost the Socialist government crucial support on the left. Scores of flights in and out of France were cancelled as air traffic controllers went on strike to try to force the government to repeal the changes that became law in July. (Photo by Thomas Samson/AFP Photo)

Wakhi nomad women milk yaks in Wakhan, Afghanistan. About 12,000 villagers live at an altitude of 4,500 metres in the harsh, desolate terrain. The Wakhi people live a simple, relaxed life with their livestock. (Photo by Eric Lafforgue/Barcroft Images)

A woman walks protecting herself from rain after Hurricane Matthew in Les Anglais, Haiti, October 13, 2016. (Photo by Andres Martinez Casares/Reuters)

A truck driver cleans the mirror of his decorated truck in Charsadda outside Peshawar, Pakistan October 18, 2016. (Photo by Fayaz Aziz/Reuters)

A woman carries her child in a basket as she walks on a road in Allahabad, India, August 11, 2016. (Photo by Jitendra Prakash/Reuters)

This handout picture taken on December 13, 2016 and released on December 14, 2016 by the Tiergarten Schoenbrunn zoo in Vienna, Austria, shows a baby sloth eating some salad as it hangs on it's mother's belly in their enclosure. The baby was born already on November 18, 2016, but according to the zoo it could be picured for the first time only now as it usually hides in it's mother's soft coat. (Photo by Daniel Zupanc/AFP Photo)

In this Tuesday, December 20, 2016 photo, Mohammad Ramzan, right, reacts while talking to The Associated Press with his young bride Saima in Jampur, Pakistan. Saima was given as a bride to the older man by her father so he could marry the groom’s sister, a practice of exchanging girls that is entrenched in conservative regions of Pakistan. It even has its own name in Urdu: Watta Satta, “give and take”. A mix of interests – family obligations, desire for sons, a wish to hand off a girl to a husband – can lead to a young teen in an a marriage she never sought. (Photo by K.M. Chaudhry/AP Photo)

A reef shell lies on a beach as the sun sets on Lady Elliot Island located north-east of the town of Bundaberg in Queensland, Australia, June 10, 2015. UNESCO World Heritage delegates recently snorkelled on Australia’s Great Barrier Reef, thousands of coral reefs, which stretch over 2,000 km off the northeast coast. Surrounded by manta rays, dolphins and reef sharks, their mission was to check the health of the world's largest living ecosystem, which brings in billions of dollars a year in tourism. Some coral has been badly damaged and animal species, including dugong and large green turtles, are threatened. UNESCO will say on Wednesday whether it will place the reef on a list of endangered World Heritage sites, a move the Australian government wants to avoid at all costs, having lobbied hard overseas. Earlier this year, UNESCO said the reef's outlook was “poor”. (Photo by David Gray/Reuters)