Here is a list of other events that make 4/20 significant:

1871 - The Civil Rights Act of 1871 becomes law.

1916 - The Chicago Cubs play their first game at Weeghman Park (currently Wrigley Field), defeating the Cincinnati Reds 7-6 in 11 innings

1961 - Failure of the Bay of Pigs Invasion of US troops against Cuba.

1972 - Apollo 16 lands on the Moon.

1986 - Professional basketball player Michael Jordan sets all-time record for points in an NBA playoff game with 63 against the Boston Celtics.

1999 - Columbine High School massacre: Eric Harris and Dylan Klebold kill 13 people and injure 24 others before committing suicide at Columbine High School in Jefferson County, Colorado.

2001 - China removes homosexuality from its list of mental illnesses.

2008 - Danica Patrick wins the Indy Japan 300 becoming the first female driver in history to win an Indy car race.

Here are some Births that occurred on 4/20:

1808 - Napoleon III, Emperor of the French (d. 1873)

1889 - Adolf Hitler, German Chancellor (d. 1945)

So happy 420 everybody. Remember to fly high like Jordon and land on the moon like the Apollo.