Since the 1970s, people have celebrated the unofficial holiday. But why is it celebrated on 4/20 and where did the celebration originate?
However, most believe 420 Day originated in California
in the 1970s when a group of teenagers from San Rafael High School in Marian County would ritualistically smoke marijuana at 4:20 each day. The number 420 became their code for marijuana.
"Happy 420," XXL magazine posted along with a picture of actor Seth Rogen alongside rappers Snoop Dogg and Wiz Khalifa smoking marijuana "blunts."