1. In 1965, the first-ever Joint American-Soviet Spaceflight was conducted on March 18. This historic event was the highlight of the Gemini 3 mission that covered 4 hours and 52 minutes, and saw the two countries work together in outer space.

2. On March 18, 1927, the infamous St. Francis Dam disaster occurred, which claimed the lives of more than 400 people. Located in Los Angeles County, the dam had collapsed due to insufficient construction, and a heavy rainstorm.

3. In 1937, California Highway 101, the longest-running highway in the state, was completed, thus making road travel between Los Angeles and San Francisco considerably easier.

4. On March 18, 1959, a devastating earthquake that measured 6.4 on the Richter scale hit the San Fernando Valley area in Los Angeles, causing over 100 fatalities and widespread property damage.

5. The Golden Gate Bridge, one of the most iconic landmarks in California, received its final coat of paint on March 18, 1937. The 1.7-mile suspension bridge is considered to be one of the largest bridges of its kind in the world, and attracts millions of tourists from around the world annually.