Albert Hoffman, the Swiss chemist who discovered the popular recreational drug lysergic acid diethylamide (LSD), has died at the age of 102 at his home on Basel. The New York Times obituary can be found here.

Although he discovered the chemical in 1938, he did not discover its psychotropic effects for five years. According to the Times,

It was during his work on the ergot fungus, which grows in rye kernels, that he stumbled on LSD, accidentally ingesting a trace of the compound one Friday afternoon in April 1943. Soon he experienced an altered state of consciousness similar to the one he had experienced as a child.

On the following Monday, he deliberately swallowed a dose of LSD and rode his bicycle home as the effects of the drug overwhelmed him. That day, April 19, later became memorialized by LSD enthusiasts as “bicycle day.”

LSD went on, of course, to become a mainstay of the counterculture of the 1960s, and continues to cycle in and out of popularity to this day. Its effects were intensively researched by the US Army and CIA, but it was illegalized by various state governments in the US in 1966.