Gas-masked men of the British Machine Gun Corps with a Vickers machine gun during the first battle of the Somme, 1916. (Photo by General Photographic Agency/Getty Images)

A re-enactor poses for a portrait before a re-enactment of the Battle of Hastings, commemorating the 950th anniversary of the battle, in Battle, Britain October 15, 2016. Some thousands of history buffs including many in full costume marked the 1066 Battle of Hastings with a dramatic reenactment that commemorates one of the most important events in British history. (Photo by Neil Hall/Reuters)

People dressed in the historic uniforms of the Imperial Russian army take part in a re-enactment of the 1812 Battle of Berezina, to mark the 204th anniversary of the battle, near the village of Bryli, Belarus, November 27, 2016. (Photo by Vasily Fedosenko/Reuters)

A history enthusiast, dressed as a soldier, marches before the re-enactment of Napoleon's famous battle of Austerlitz near the southern Moravian town of Slavkov u Brna, Czech Republic December 3, 2016. (Photo by David W. Cerny/Reuters)

Turkish Kurds watch the Syrian town of Kobani from near the Mursitpinar border crossing, on the Turkish-Syrian border in the southeastern town of Suruc, October 19, 2014. (Photo by Kai Pfaffenbach/Reuters)

Iraqi pro-government forces fire an anti-tank cannon near al-Sejar village, north-east of Fallujah, on May 25, 2016, as they take part in a major assault to retake the city from the Islamic State (IS) group. Iraqi forces, consisting of special forces, soldiers, police, paramilitary-fighters and pro-government tribesmen, launched a major assault to retake Fallujah, the scene of deadly battles during the US occupation and one of the toughest targets yet in Baghdad's war on the Islamic State group. (Photo by Ahmad Al-Rubaye/AFP Photo)

Young African lion Asali (R) jumps for a bungee-ball toy as her father Jambo or “Bruiser” looks on at the opening of a savannah-themed makeover of the lion enclosure at Taronga Zoo August 29, 2006 in Sydney, Australia. The renovation includes sandstone rock features, a wading pool, and red ochre crushed granite substrate in a move to make the enclosure more closely resemble the natural habitat of the African savannah. (Photo by Ian Waldie/Getty Images)

A videographer uses a drone as he takes a video of a model presenting a lingerie creation at the rehearsal for Eve's Temptation collection during China Fashion Week in Beijing, October 26, 2014. (Photo by Kim Kyung-Hoon/Reuters)