1. In 1880, the Los Angeles and San Gabriel Valley Railroad completed its first passenger service stretch from Pasadena to Los Angeles, marking the beginning of regular commuter travel between the two cities.

2. In 1917, the United States entered World War I. Many Californians participated in the war effort, including soldiers, workers in the shipyards and airplane factories, and civilians who supported the Red Cross and other organizations.

3. In 1968, one of the largest oil spills in U.S. history occurred off the coast of California, when the supertanker SS Santa Barbara ruptured its hull and spilled over 100,000 barrels of crude oil into the Santa Barbara Channel. The disaster led to significant environmental activism and legislation, including the Environmental Protection Agency and the Clean Water Act.

4. In 1970, the California State Board of Education approved a plan to integrate schools in the state's largest cities, including Los Angeles, San Francisco, and Oakland. The plan was met with resistance from some, but ultimately contributed to significant strides in civil rights and education.

5. In 2005, the California State Assembly approved a bill legalizing same-sex marriage in the state. The bill was vetoed by Governor Arnold Schwarzenegger, but later led to the landmark court decision in 2008 that struck down California's ban on same-sex marriage, which was ultimately upheld by the U.S. Supreme Court in 2013.