Andy Gibb struggled with substance abuse and died of a heart ailment in 1988, just prior to his 30th birthday.
Jim Morrison was found dead in his Paris apartment at the age of 27. No official cause was ever revealed, though most believe he died of a heroin overdose.
Tupac Shakur was shot 13 times in 1996. He died at the age of 25, though some folks believe he's still alive.
Biggie was murdered in a drive-by shooting at the age of 24. The killer was never brought to justice.
Bob Marley, a reggae icon, passed way in 1981 at age 36 after a long battle against melanoma.
John Lennon was killed at the age of 40. He was shot in the street following a recording session in New York City.