Albert Hofmann, a Swiss chemist, first synthesised LSD in 1938. In 1943 he discovered its psychoactive effect during a self-experiment that became known as "Bicycle Day". Originally developed for psychiatry, LSD later became an icon of the counterculture. Hofmann regretted its misuse but always saw therapeutic potential in it. He died at the age of 102, just as research into psychedelic substances was reviving.