A man holds on a rope as he tries to board a truck while crossing floodwaters brought by typhoon Koppu that battered Candaba town, Pampanga province, north of Manila October 20, 2015. Typhoon Koppu swept across the northern Philippines killing at least nine people as trees, power lines and walls were toppled and flood waters spread far from riverbeds, but tens of thousands of people were evacuated in time. (Photo by Romeo Ranoco/Reuters)

Graffiti is painted on the bathroom walls at a restaurant in the Williamsburg area of Brooklyn borough in New York, United States, October 1, 2015. Some 2.4 billion people around the world don't have access to decent sanitation and more than a billion are forced to defecate in the open, risking disease and other dangers, according to the United Nations. To mark World Toilet Day on November 19, Reuters photographers captured pictures of toilets in cities, towns and villages around the globe. (Photo by Shannon Stapleton/Reuters)

Ukrainian President Petro Poroshenko gestures during a news conference in Kiev, Ukraine, June 5, 2015. REUTERS/Mykhailo Markiv/Ukrainian Presidential Press Service/Pool

Mercedes driver Nico Rosberg, right, of Germany steers his car in front of Mercedes driver Mercedes driver Lewis Hamilton of Britain, center and Ferrari driver Sebastian Vettel of Germany during the Austrian Formula One Grand Prix race at the Red Bull Ring in Spielberg, southern Austria, Sunday, June 21, 2015. (AP Photo/Kerstin Joensson)

A group of youngsters dressed as ghouls and zombies for Halloween parade in downtown Lisbon, Portugal, Friday, October 31, 2014. (Photo by Francisco Seco/AP Photo)

A tunnel with electric switches are seen in Josip Broz Tito's underground secret bunker (ARK) in Konjic, October 16, 2014. In the early 1950s, Josip Broz Tito, the late leader of the former Yugoslavia, ordered the building of the secret bunker, located 900 feet (270 m) underground and near the Bosnian town of Konjic, to safeguard the country's ruling class in case of a nuclear attack. Construction at the complex, which had a cost equivalent price tag of $4.6 billion, continued until 1979, the year before Tito died. (Photo by Dado Ruvic/Reuters)

A winter swimmer, wearing a Santa Claus hat to celebrate the upcoming Christmas, reacts as he plays on a frozen lake at a park in Shenyang, Liaoning province, December 22, 2014. The characters on the hat read: “Shenyang Winter Swimming”. (Photo by Reuters/Stringer)

Relatives of the crashed AirAsia plane passengers pray at Juanda Airport, in Surabaya, Indonesia, 31 December 2014. Indonesian rescuers retrieved three more bodies from the sea on 31 December but the search to recover more victims from the AirAsia plane crash was hampered by bad weather, the recue chief said. AirAsia Indonesia flight QZ8501 crashed into the Java Sea on 28 December, about halfway through a two-hour flight between Surabaya, Indonesia's second largest city, and Singapore. (Photo by Made Nagi/EPA)