Princess Grace died on September 14, 1982 in Monacoville, Monaco in a car accident when she was 52 years old. While driving she reportedly suffered a stroke. Grace Kelly was buried at the Cathedral of St. Nicholas in Monte Carlo, Monaco. Prince Rainier III died on April 6, 2005, after fighting a long battle with lung, heart, and kidney problems. He was 81 years old at the time of his death. He was buried in a white marble tomb next to his wife, Princess Grace of Monaco.