Walter Elias Disney died on Dec. 15, 1966 during the production of The Jungle Book. He was a chain smoker, suffered from a chronic cough that alerted others to the fact that he was in the room, and eventually died from complications from lung cancer.
Little more than a month before his death, he checked into hospital to undergo surgery related to what he thought was an old polo injury. But x-rays revealed a large lesion on his left lung, which turned out to be a tumour. Doctors performed a pneumonectomy — removing the entire lung — and estimated that Walt would return to work four-to-six weeks later.
“There is no reason to predict any recurrence of the problem or curtailment of his future,” doctors told United Press International. That article was printed on Nov. 23, 1966. Within two weeks, he died of acute circulatory failure.