On this day in 1943, Swiss chemist Dr. Albert Hofmann first discovered the psychedelic effects of lysergic acid diethylamide (LSD) through unintentional exposure to the substance. Dr. Hofmann first synthesized LSD in 1938, then decided to revisit its synthesis on April 16, 1943, when he accidentally ingested a small amount and noticed its distinctive effects. maps.org/lsd | Multidisciplinary Association for Psychedelic Studies (MAPS)