Nearly 40 years after
Reefer Madness (1936) (aka "Reefer Madness") was made, it was found again in 1972 by
Keith Stroup, founder of The National Organziation for Reform of Marijuana Laws, who discovered it in the Library of Congress archives and paid $297 for a print. He screened it in New York as a benefit for the advocacy group, and the rest is cult history.