Whooo … are … you?” – Alice d. On April 19, 1943, Albert Hofmann ingested 0.25 milligrams (250 micrograms) of LSD. Between one and two hours later, Hofmann experienced slow and gradual changes in his perception. He asked his laboratory assistant to escort him home. Due to wartime restrictions on automobile use, they made the journey by bicycle. 

On the way, Hofmann became anxious as objects in his field of vision wavered and distorted as if seen in a convex mirror. Upon arriving home, Hofmann’s condition rapidly deteriorated as he struggled with feelings of anxiety, alternating in his beliefs that the next-door neighbor was a malevolent witch, that he was going insane, and that the LSD had poisoned him. When the house doctor arrived, however, he could detect no physical abnormalities, save for a pair of widely dilated pupils. Hofmann was reassured, and soon his terror began to give way to a sense of good fortune and enjoyment, as he later wrote:

… Little by little I could begin to enjoy the unprecedented colors and plays of shapes that persisted behind my closed eyes. Kaleidoscopic, fantastic images surged in on me, alternating, variegated, opening and then closing themselves in circles and spirals, exploding in colored fountains, rearranging and hybridizing themselves in constant flux …

The events of this first LSD trip, now known as “Bicycle Day” in memory of Hofmann’s bicycle ride home, proved to Hofmann that he had indeed made a significant discovery: a psychoactive substance with extraordinary potency, capable of causing significant shifts of consciousness in incredibly low doses. (The term trip was first coined by US Army scientists during the 1950s when they were experimenting with LSD.) Hofmann foresaw the drug as a powerful psychiatric tool; because of its intense and introspective nature, he could not imagine anyone using it recreationally. Bicycle Day is increasingly observed in psychedelic communities as a day to celebrate the discovery of LSD. – Wiki –