Tsar Alexander II (1818–1881) known as “The Liberator” lying in state. He was mortally wounded by an assassination attack in St Petersburg. (Photo by Hulton Archive/Getty Images). March 1881

8 May 2001: Ronnie O'Sullivan of England poses for pictures at the Hilton Hotel with the trophy and his girlfriend Bianca Westwood after winning Embassy World Championship Snooker Final in Sheffield.

Two guards perform an execution in China, one holding the gun, the other holding a mask over the victim's face. (Photo by General Photographic Agency/Getty Images). Circa 1925

The civilised world lies on its knees, a sickness wracking its body. The affliction causes a necrotising of tissues so perfectly uniform in distribution that victims take on the appearance of corpses long before death occurs due to organ failure or secondary infections. ...

Dance Team Rage Crew perform at BAFTA LA's 6th Annual Christmas Party and Toy Drive at Helen Keller Park on December 17, 2011 in Los Angeles, California. (Photo by Frazer Harrison/Getty Images)

A Pakistani scavenger girl writes on a notebook she collected from a garbage, while another girl sits next to her in Lahore, Pakistan, Wednesday, April 1, 2015. Thousands of children pick recyclable items from waste dumping points to earn living for their poor families. (Photo by K. M. Chaudary/AP Photo)

Revelers, covered in coloured powder, celebrate, during a Holi Run Festival in Madrid, Spain, Sunday, April 12, 2015. Thousands of revelers took part in the festival that includes a mini marathon. The festivals are fashioned after the Hindu spring festival Holi, which is mainly celebrated in the north and east of India. (Photo by Andres Kudacki/AP Photo)