1. March 20, 1852: The Town of Sonoma Officially Becomes a City
On this day in 1852, the town of Sonoma, located in Northern California, officially became a city. Founded in 1823 as a mission, Sonoma played a significant role in the Bear Flag Revolt of 1846 and was the capital of California for a short time. Today, the city is known for its rich history and wine industry.

2. March 20, 1933: Los Angeles Dam Bursts
One of the most significant floods in California history occurred on March 20, 1933, when the Los Angeles Dam failed, resulting in the loss of many lives and massive damage to property. The disaster prompted the state to take a more active role in dam safety and flood control.

3. March 20, 1969: John Lennon and Yoko Ono's Bed-In at the Fairmont Hotel
On March 20, 1969, John Lennon and Yoko Ono arrived in San Francisco to conduct their famous Bed-In at the Fairmont Hotel. The event was a protest against the Vietnam War and was accompanied by the recording of their hit song, "Give Peace a Chance."

4. March 20, 1985: First Commercially Successful Vineyard in Mendocino County
On March 20, 1985, the first commercially successful vineyard in Mendocino County was established. Today, Mendocino boasts some of the finest vineyards in California, producing a variety of robust wines.

5. March 20, 2019: Great Floods of Southern California
On March 20, 2019, Southern California experienced heavy rains, causing significant flooding and mudslides in many areas. The storm resulted in the closure of several schools, roads, and businesses, and many residents were evacuated from their homes. This was a reminder of the importance of disaster preparedness in California.