Ari Onassis was a Greek shipping magnate who made his fortune in the 1950s and 1960s. He was one of the wealthiest people in the world at the time and owned a large fleet of oil tankers. Onassis was also known for his philanthropy and was a major donor to charities and universities. He was married to Jacqueline Kennedy Onassis, the widow of President John F. Kennedy. Onassis died in 1975 at the age of 69.