On Jan. 11, 1964, U.S. Surgeon General issued the first government report on the risks associated with smoking, admitting that cigarettes can cause lung cancer.
Here's what the report said about cigarettes and mortality, which sounded groundbreaking at the time:
National Institutes of Health
And the conclusion:
National Institutes of Health
This wasn't the first time that a link had been drawn between smoking and lung cancer - in 1957, Surgeon General Leroy E. Burney said evidence is "increasingly pointing in one direction: that excessive smoking is one of the causative factors in lung cancer."
The 1964 report, however, was the first formal and conclusive warning that cigarettes can cause cancer.
Read the full report here.