Bicycle Day
This holiday is featured in the Obscure Holiday Calendar app with emoji-style visuals, reminders, and daily fun facts.
Overview
Bicycle Day, celebrated annually on April 19th, commemorates the first intentional acid trip by Swiss chemist Albert Hofmann in 1943. After self-administering what he believed to be a small dose of lysergic acid diethylamide (LSD-25) in his laboratory, Hofmann experienced its profound psychoactive effects while cycling home, accompanied by his assistant. This pivotal event marked the discovery of LSD's psychedelic properties and is widely recognized as a significant moment in the history of psychedelic research and counter-culture.
Observed each year on April 19, Bicycle Day invites people to pause, share the story, and bring a little themed joy to their day.
Origin and story
Albert Hofmann first synthesized LSD-25 in 1938 while researching ergot alkaloids, but its psychoactive effects were not discovered until his 1943 self-experiment.
Hofmann's self-administered dose on Bicycle Day was 250 micrograms, an amount he believed to be a threshold dose, but is actually a significant dose of LSD.
Quick facts
- DateApril 19
- TypeCultural / community observance
- Great forFriends, Families, Classrooms, Teams
Also on this date
Ways to celebrate
- Plan something small on April 19: a quick nod to Bicycle Day with friends, family, or coworkers.
- Share one fast fact about Bicycle Day: Albert Hofmann first synthesized LSD-25 in 1938 while researching ergot alkaloids, but its psychoactive effects were not discovered until his 1943 self-experiment.
- Post a story with #bicycle-day and invite others to try a tiny activity.
- Pair music, snacks, or décor that match the theme and enjoy a small break.
- Write a note or journal entry on why Bicycle Day matters, then set a reminder for next year.
Fun facts
- Albert Hofmann first synthesized LSD-25 in 1938 while researching ergot alkaloids, but its psychoactive effects were not discovered until his 1943 self-experiment.
- Hofmann's self-administered dose on Bicycle Day was 250 micrograms, an amount he believed to be a threshold dose, but is actually a significant dose of LSD.
- The first public celebration of 'Bicycle Day' was organized by Thomas B. Roberts, a professor at Northern Illinois University, in 1985, decades after the original event.
Sources and attribution
Source not provided.
Continue to
FAQ
- When is Bicycle Day?
- It is observed on April 19 each year.
- What is Bicycle Day?
- Bicycle Day, celebrated annually on April 19th, commemorates the first intentional acid trip by Swiss chemist Albert Hofmann in 1943. After self-administering what he believed to be a small dose of lysergic acid diethylamide (LSD-25) in his laboratory, Hofmann experienced its profound psychoactive effects while cycling home, accompanied by his assistant. This pivotal event marked the discovery of LSD's psychedelic properties and is widely recognized as a significant moment in the history of psychedelic research and counter-culture.
- How do people celebrate Bicycle Day?
- Plan something small on April 19: a quick nod to Bicycle Day with friends, family, or coworkers.
Get the app
Thousands of obscure holidays, daily widgets, reminders, and fun facts—free on iOS and Android.