Schwarzenegger began weight training at the age of 15. He won the Mr. Universe title at age 20 and went on to win the Mr. Olympia contest seven times. Schwarzenegger has remained a prominent presence in bodybuilding and has written many books and articles on the sport. Schwarzenegger gained worldwide fame as a Hollywood action film icon. He was nicknamed the "Austrian Oak" and the "Styrian Oak" in his bodybuilding days, "Arnie" during his acting career and more recently "The Governator" (a portmanteau of "Governor" and "The Terminator" – one of his best-known movie roles).

Members of a teenage girl gang convincing an unwilling recruit to join the gang, circa 1955. (Photo by Vecchio/Three Lions)

An ancient oak tree sits in a Shropshire field as the first signs of Spring begin to show across the United Kingdom on February 19, 2014 in Bridgnorth, England. (Photo by Christopher Furlong/Getty Images)

A pilot inflates a hot air balloon while taking part in the 38th International Balloon Festival of Chateau-d'oex, Switzerland, 23 January 2016. The festival takes place from 23 to 31 January. (Photo by Vincent Vannay/EPA)

People sit next to a pool where the Tower of Madrid skyscraper is reflected at sunset in Madrid, Thursday, November 26, 2015. The tower was the tallest in Spain since it was finished in 1957 until 1982. (Photo by Francisco Seco/AP Photo)

New Zealand photographer Niki Boon captured her children, who are growing up with limited electronics, in the photo series “Childhood in the Raw Photos”. Niki Boon began taking photos as a hobby while she was working as a physiotherapist in Scotland. However, the New Zealand native found her interest in the art waning while she travelled, and it wasn’t until she had returned home and started raising a family that her passion was rekindled. “Childhood in the Raw”, an ongoing photo series of her four children’s technology-free life on her 10-acre property in New Zealand, is the perennial fruit of this passion. (Photo by Niki Boon)

A boat commutes across the Mekong river in Phnom Penh on August 8, 2014. The Mekong is the world's twelth longest river running from the Tibetan Plateau through China's Yunnan province, Myanmar, Laos, Thailand, Cambodia and Vietnam. (Photo by Tang Chhin Sothy/AFP Photo)