Albert Hofmann accidentally discovers the hallucinogenic effects of the research drug LSD. He intentionally takes the drug three days later on April 19.

Albert Hofmann was a Swiss chemist known for being the first to synthesize, ingest, and learn of the psychedelic effects of lysergic acid diethylamide (LSD). Hofmann's team also isolated, named and synthesized the principal psychedelic mushroom compounds psilocybin and psilocin. Hofmann discovered the structure of chitin in 1929. He authored more than 100 scientific articles and numerous books, including LSD: Mein Sorgenkind. In 2007, he shared first place with Tim Berners-Lee on a list of the 100 greatest living geniuses published by The Daily Telegraph.