A reveller takes part in the Holi Party Festival at Niemeyer Center in Aviles, northern Spain, August 27, 2016. (Photo by Eloy Alonso/Reuters)

Revellers battle with tomato pulp during the annual “Tomatina” (tomato fight) festival in Bunol near Valencia, Spain, August 31, 2016. (Photo by Heino Kalis/Reuters)

In this Friday, November 6, 2015 photo dancers Alba Ibanez, right, and Luis Chavez, both from Spain, dress up backstage before taking part in the World Salsa Master dance competition in Madrid. Ten dance couples from different countries around the world performed in front of an audience of around 2,000 people. Participants – who wore bright, colorful outfits – came from the United States, Italy, Spain, Portugal, Mexico, Chile, Uruguay, Czech Republic and Venezuela. (Photo by Francisco Seco/AP Photo)

A woman dressed as a Viking drinks local red wine during the annual Viking festival of Catoira in north-western Spain August 2, 2015. The festival re-enacts past Viking raids in the area and is celebrated annually on the first Sunday in August. (Photo by Miguel Vidal/Reuters)

A girl rides a donkey as another walks by at the Shawqaba camp for internally displaced people who were forced to leave their villages by the war in Yemen's northwestern province of Hajjah March 12, 2016. In northwest Yemen, one of the poorest countries in the Middle East, about 400 families uprooted by the war have been stuck in the Shawqaba camp in Hajjah province for the past year. Residents live in poorly built huts that protect them neither from summer heat nor winter cold in a camp that lacks the most basic services. (Photo by Abduljabbar Zeyad/Reuters)

Rebel fighters from the Jaish al- Fatah (or Army of Conquest) brigades manoeuver an alleged explosive- rigged make- shift armoured vehicle during a major assault on Syrian government forces West of Aleppo city on October 28, 2016 Syrian opposition fighters launched a major assault on government forces to break a months- long siege of rebel- held neighbourhoods of the battered city of Aleppo. Rebel groups including the powerful Ahrar al- Sham faction and former Al- Qaeda affiliate Fateh al- Sham Front fired waves of rockets into government- held western Aleppo, killing at least 15 civilians, a monitor said. (Photo by Omar Haj Kadour/AFP Photo)

Men are held by Iraqi national security agents, to be interrogated at a checkpoint, as oil fields burn in Qayara, south of Mosul, Iraq, Saturday, November 5, 2016. Islamic State fighters launch counterattacks in the thin strip of territory Iraqi special forces have recaptured in eastern Mosul, highlighting the challenges ahead as the battle moves into more densely populated neighborhoods where coalition air power must be used more selectively. (Photo by Felipe Dana/AP Photo)

A man and a woman both wounded by what locals say was recent shelling by Ukrainian forces, react as they sit in an ambulance in Donetsk August 23, 2014. (Photo by Maxim Shemetov/Reuters)