Albert Hofmann, the Swiss chemist who discovered the hallucinogenic drug LSD, has died of a heart attack at his home in Basel at the age of 102.
Mr Hofmann first produced LSD in 1938 while researching the medicinal uses of a crop fungus.
He accidentally ingested some of the drug and said later: "Everything I saw was distorted as in a warped mirror."
He argued for decades that LSD could help treat mental illness, but in the 1960s it became a popular street drug.
'Turn on, tune in, drop out'
While working with the drug in the Sandoz pharmaceutical laboratory a few years after first producing it, Mr Hofmann ingested some of the drug through his fingertips.
He went home and experienced what he described as visions of "fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colours".
The drug was popularised by Harvard professor Timothy Leary who suggested that people "turn on, tune in, drop out".
Rock stars and the counter-culture of the 1960s picked up LSD as a wonder drug but horror stories began to emerge of users suffering permanent psychological damage.
LSD was made illegal in many countries beginning in the late 1960s.