1. Missouri Became a State on March 3, 1821
March 3 is a significant day in Missouri's history because it is the day the state became an official member of the United States. On March 3, 1821, Missouri was admitted as the 24th state in the Union.

2. The Battle of Pea Ridge Took Place on March 3-4, 1862
On March 3-4, 1862, the Battle of Pea Ridge was fought in northwest Arkansas, near the Missouri border. Missouri soldiers played a significant role in this Civil War battle, which resulted in a Union victory and helped secure Missouri for the Union cause.

3. The Saint Louis Science Center Opened on March 3, 1963
The Saint Louis Science Center, one of Missouri's most popular attractions, opened its doors on March 3, 1963. Since then, millions of visitors have enjoyed the center's exhibits and programs focused on science, technology, engineering, and math.

4. Missouri Hosted Its First Presidential Primary on March 3, 1984
On March 3, 1984, Missouri held its first-ever presidential primary. The primary was notable for being the first in the nation to use a "winner-takes-all" format, in which the candidate who won the most votes received all of the state's delegates.

5. The 2012 Midwest Tornado Outbreak Struck on March 3, 2012
On March 3, 2012, a massive tornado outbreak swept through the Midwest, including parts of Missouri. The outbreak resulted in more than 40 tornadoes and was responsible for 41 deaths, including eight in Missouri. The damage was estimated at more than $1.5 billion.