Participant wearing medieval costumes perform during an annual re-enactment of a battle near the village of Libusin, Czech Republic, April 23, 2016. About 2000 enthusiasts have come to simulate the medieval battle during the 24rd annual swordsmen gathering in Libusin village. (Photo by David W. Cerny/Reuters)

Iraqi forces launch a rocket in Mosul's eastern Al-Intisar neighbourhood on December 30, 2016, during an ongoing military operation against Islamic State (IS) group jihadists. Iraqi forces advanced on December 29 after declaring a new phase in their offensive on eastern Mosul, stepping up efforts to reclaim the Islamic State group's last major stronghold in the country. (Photo by Ahmad Al-Rubaye/AFP Photo)

Participants re-enact the “Battle of Five Armies” from J.R.R. Tolkien's novel “The Hobbit” in a forest near the town of Doksy, Czech Republic June 6, 2015. According to event organizers, hundreds of enthusiasts dressed as characters such as elves, dwarves, goblins and orcs from the book “The Hobbit” re-enacted the clash. (Photo by David W. Cerny/Reuters)

A Baby sumatran orangutan (Pongo abelii) plays around in a tree as they train at Sumatran Orangutan Conservation Programme's rehabilitation center on November 12, 2016 in Kuta Mbelin, North Sumatra, Indonesia. The Orangutans in Indonesia have been known to be on the verge of extinction as a result of deforestation and poaching. Found mostly in South-East Asia, where they live on the islands of Sumatra and Borneo, the endangered species continue to lose their habitat as a result of corporate expansion in a developing economy. Indonesia approved palm oil concessions on nearly 15 million acres of peatlands over the past years and thousands of square miles have been cleared for plantations, including the lowland areas that are the prime habitat for orangutans. (Photo by Ulet Ifansasti/Getty Images)

Wolfgang (L), member of World War One historical association “Darstellungsgruppe Suddeutsches Militar 1870-1918” (DSM 18), from Munich, Germany, and Florent, member of French association “Le Poilu de la Marne”, dressed in vintage army uniforms, visit the Bezonvaux bunker in the national forest of Verdun, eastern France, March 29, 2014. Members of French and German historical associations, who gather annually, together visited the battlefield of Verdun in France, the site of a bloody World War One battle that dragged on for around 10 months in 1916, claiming hundreds of thousands of lives and destroying many villages. (Photo by Charles Platiau/Reuters)

Participants wearing medieval costumes re-enact the 1620 battle of Bila Hora between Bohemian Estates and Austrian Imperial with Catholic forces in Prague, Czech Republic September 18, 2016. (Photo by David W. Cerny/Reuters)

Revellers take part in the annual “Naval Battle” of Vallecas during the Virgen del Carmen Festival in Madrid, Spain July 17, 2016. (Photo by Javier Barbancho/Reuters)

A Kurdish female fighter from the People's Protection Units (YPG) gestures as she carries her weapon near al-Hawl area where fighting between Islamic State fighters and fighters from Democratic Forces of Syria are taking place in south-eastern city of Hasaka, Syria November 10, 2015. (Photo by Rodi Said/Reuters)