Albert Hofmann, the pioneering Swiss chemist and advocate of psychedelics who discovered the hallucinogenic properties of LSD, died Tuesday. He was 102.

Hofmann reportedly died of a heart attack at his home in Basel, Switzerland.

Hofmann's most famous discovery happened on April 16, 1943. He was researching the synthesis of a lysergic acid compound, LSD-25, when he inadvertently absorbed a bit through his fingertips. Intrigued by the effect it had on his perception, Hofmann decided further exploration was warranted. Three days later, on April 19, he ingested 250 milligrams of LSD, embarking on the first full-fledged acid trip. That day became known among LSD fans as "bicycle day" because Hofmann began experiencing the drug's intense effects on his bicycle trip home from the lab.