Chinese Language Day is an annual observance held on April 20. It was established in 2010 by the UNESCO along with the rest of the official Language Days in the United Nations. These Days focus on promoting multilingualism and cultural diversity.
April 20 is a counterculture holiday dedicated to smoking and celebrating cannabis. It is typically written as 420 or 4/20.
On April 20, Russia celebrates National Donor Day. This date was chosen to commemorate the first successful blood transfusion in Russia, which took place on April 20, 1832. It was performed by a young obstetrician Andrey Wolf to save the life of a woman in labor who had an obstetric hemorrhage.