A couple sunbath on the beach in Ostrowo, northern Poland, July 20, 2015. Picture taken July 20, 2015. (Photo by Kacper Pempel/Reuters)

A general view shows smoke and volcanic ashes billowing from volcano Cotopaxi in Pedregal, Ecuador, late 07 October 2015. (Photo by Jose Jacome/EPA)

People dressed in costumes have a break while marching during the Vijanera Festival, in the small village of Silio, northern Spain, Sunday, January 3, 2016. The Vijanera masquerade, of pre-Roman origin, is the first carnival of the year in Europe symbolizing the triumph of good over evil and involving the participation of crowds of residents wearing different masks, animal skins and brightly coloured clothing with its own complex function and symbolism and becoming the living example of the survival of archaic cults to nature. (Photo by Francisco Seco/AP Photo)

Venezuela: An anti-government protester wearing a Guy Fawkes mask throws a molotov cocktail at the Bolivarian National Police during clashes in Caracas, Venezuela, Thursday, April 17, 2014. Opposition protesters have been demonstrating against high crime, high inflation and shortages of basic goods since mid-February. (Photo by Ramon Espinosa/AP Photo)

HMS Dragonís Mk8 Lynx Helicopter conducted day into night flying serial by L(Phot) Dave Jenkins which won the Media Operations Category which was awarded to the best single image that is judged to create the most impact as a news in the annual Peregrine Trophy awards. (Photo by Dave Jenkins/PA Wire)

This bat gives a cheeky smile as he gobbles down his food at Singapore Zoo, on September 10, 2013. (Photo by Benny Iskander/HotSpot Media)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)

Two Inuit children at Point Barrow, Alaska, holding the tusks of a large walrus, probably killed for food, circa 1930. (Photo by General Photographic Agency/Getty Images)