Female Chimpanzee “Fifi” eats carrots as she sits in her enclosure at Taronga Zoo on her 60th birthday May 21, 2007 in Sydney, Australia. Fifi is the oldest of the Zoo's chimp population, which consists of 19 individuals. (Photo by Ian Waldie/Getty Images)

Nationalist youths throw bottles at police officers after the annual Orange march on July 12, 2016 in Belfast, Northern Ireland. The controversial Ardoyne interface is a flash point between the Catholic and Protestant communities with trouble flaring in the area frequently during the so called marching season. The Protestant Orange bands from the nearby area have been stopped from parading past the Catholic Ardoyne for the past three years. (Photo by Charles McQuillan/Getty Images)

Commonwealth dance group on the right track with Virgin Trains – Photo call at Glasgow Central Station. (Photo by Daily Record)

A man smashes an apple with a sword placed on the head of a man wearing a knave costume during the Easter knight event on April 21, 2014 in Berlin. The easter knight event delivers an insight into medieval lifestyle. (Photo by Rainer Jensen/AFP Photo/DPA)

Britain's skip Eve Muirhead, right, embraces Anna Sloan after defeating Switzerland to win the women's curling bronze medal at the 2014 Winter Olympics, Thursday, February 20, 2014, in Sochi, Russia. (Photo by Robert F. Bukaty/AP Photo)

A cadet lies on the grass after collapsing during a promotion ceremony at a police school in Bogota December 7, 2012. (Photo by John Vizcaino/Reuters)

A general view of the sunrise over Hawes, Wensleydale, UK on November 24, 2014. (Photo by Neil Squires/PA Wire)

Hot air balloons fly over the sky in Chiang Mai province, northern Thailand, December 6, 2014. The two-day International Balloon festival 2014 featuring balloon pilots from Germany, Spain, Netherlands, Britain, and Czech Republic is held on December 06-07 2014 to celebrate Thai King Bhumibol Adulyadej's 87th birthday and also aimed to promote the tourism industry in Chiang Mai northern city. (Photo by Pongmanat Tasiri/EPA)