1. California became a state: On March 21, 1850, California officially became the 31st state of the United States of America.

2. The birth of Rosie Casals: On March 21, 1948, tennis player Rosie Casals was born in San Francisco, California. She went on to win numerous titles and was inducted into the International Tennis Hall of Fame in 1996.

3. The San Francisco earthquake: On March 21, 1957, a magnitude 5.3 earthquake struck the San Francisco Bay Area. Although there were no deaths, the earthquake caused damage to buildings and homes.

4. The passing of Cesar Chavez: On March 21, 1993, labor leader and civil rights activist Cesar Chavez passed away in San Luis, Arizona. Chavez, who was born in Yuma, Arizona, spent much of his life fighting for the rights of farm workers in California and other Western states.

5. The beginning of the Iraq War: On March 21, 2003, the United States and its allies began the invasion of Iraq. This military conflict lasted until 2011 and had a significant impact on California's military and political landscape.