Alkar Vito runs during the Children's Alka competition in Vuckovici village, Croatia, August 23, 2015. Children's Alka is a tournament which has been held every August in the Croatian village of Vuckovici since 1955, commemorating the victory over the Ottoman Turkish administration. The tournament is named after the ring, Alka, which children have to hit with their spears. (Photo by Antonio Bronic/Reuters)

Children fall as they slide down on a float along a chute to cross a pool of water and foam during the “Letniy Gornoluzhnik” (Summer mountain puddle rider) festival at the Bobroviy Log Fun Park near the Siberian city of Krasnoyarsk, Russia, August 23, 2015. The annual competition marks the end of the summer season at the Siberian ski, rest and entertainment resort. (Photo by Ilya Naymushin/Reuters)

Two woman lie in a puddle of squashed tomatoes during the annual “Tomatina” tomato fight fiesta, in the village of Bunol, 50 kilometers outside Valencia, Spain, Wednesday, August 26, 2015. The streets of an eastern Spanish town are awash with red pulp as thousands of people pelt each other with tomatoes in the annual "Tomatina" battle that has become a major tourist attraction. At the annual fiesta in Bunol on Wednesday, trucks dumped 150 tons of ripe tomatoes for some 22,000 participants, many from abroad to throw during the hour-long morning festivities. (Photo by Alberto Saiz/AP Photo)

This combination of August 30, 2005 and July 29, 2015 aerial photos shows downtown New Orleans and the Superdome flooded by Hurricane Katrina and the same area a decade later. Katrina's powerful winds and driving rain bore down on Louisiana on August 29, 2005. The storm caused major damage to the Gulf Coast from Texas to central Florida while powering a storm surge that breached the system of levees that were built to protect New Orleans from flooding. (Photo by David J. Phillip/Gerald Herbert/AP Photo)

A group of people wearing full solid-coloured bodysuits walk along a promenade as they take part in a street art performance in Bat Yam, near Tel Aviv, Israel August 29, 2015. Some 40 people participated on Saturday in the performance, initiated by a group of artists called Prizma Ensemble, as part of the city's annual international street art and street theatre festival. The group says the performance deals with concepts of identity and movement in public spaces. (Photo by Amir Cohen/Reuters)

Sculptor Jiri Genzer of the Czech Republic carves an ice sculpture at the Disney Dreams Ice Festival in Antwerp November 27, 2014. Some 60 artists from all over the world participated in the festival, making sculptures out of around 500 tonnes of ice. The festival will open on November 29 until January 11, 2015. (Photo by Yves Herman/Reuters)

A reveller dressed up as Austrian drag queen and 2014 Eurovision song contest winner Conchita Wurst takes part in New Year's celebrations in Coin, near Malaga, southern Spain, early January 1, 2015. Villagers and revellers dressed up in funny costumes to take part in the New Year's celebration. (Photo by Jon Nazca/Reuters)

Law enforcement officers stand, with some turning their backs, as New York City Mayor Bill de Blasio speaks on a monitor outside the funeral for NYPD officer Wenjian Liu in the Brooklyn borough of New York January 4, 2015. Tens of thousands of law enforcement officers from across the country gathered on Sunday for the funeral of the second of two New York City policemen killed last month in an ambush that galvanized critics of Mayor de Blasio. (Photo by Shannon Stapleton/Reuters)