Albert Einstein died of a ruptured abdominal aortic aneurysm. Taken to the University Medical Center at Princeton, he refused treatment, arguing that he wanted to end his life "elegantly." His death occurred on April 18, 1955.
Einstein was 76 when he died, according to Biography. He first learned about the aortic aneurysm in his stomach since 1948, when he was treated for abdominal pain by Dr. Rudolph Nissen. After Einstein's death, Dr. Thomas Stoltz Harvey performed an autopsy and removed Einstein's brain without Einstein's family's knowledge, hoping that one day scientists could discover the source of Einstein's genius. The great physicist's remains were cremated and scattered, but his brain remains at Princeton.