The Synthesis
In 1938, Swiss chemist Albert Hofmann, working at Sandoz Laboratories in Basel, first synthesized lysergic acid diethylamide (LSD-25) as part of a research program investigating ergot alkaloids for potential pharmaceutical applications. The compound was set aside after initial animal tests showed no particularly interesting properties.
The Accidental Discovery
Five years later, on April 16, 1943, Hofmann decided to re-examine LSD-25 on a hunch. While re-synthesizing the compound, he inadvertently absorbed a small quantity through his fingertips. He soon experienced restlessness, dizziness, and "an extremely stimulated imagination" with "an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors."
Bicycle Day
Intrigued, Hofmann intentionally ingested 250 micrograms on April 19, 1943, believing it to be a minimal dose. It was, in fact, a strong dose. As the effects intensified, he asked his laboratory assistant to escort him home by bicycle, as wartime restrictions prohibited automobile use. The ride home became a legendary journey through altered perception that is now celebrated annually as "Bicycle Day."
Legacy
Hofmann later called LSD "medicine for the soul" and advocated for its responsible use throughout his life. He lived to the age of 102, passing away in 2008. His accidental discovery opened an entirely new chapter in neuroscience, psychiatry, and the cultural history of the 20th century.