1. California's first railroad was completed on December 23, 1869. The Central Pacific and Union Pacific railroads were connected at Promontory Summit, Utah, creating the first transcontinental railroad in the United States. This allowed for easier transportation of goods and people between the East and West coasts and was a major milestone in the development of California.

2. On December 23, 1913, the Los Angeles Aqueduct was completed. The aqueduct is a system of pipes and canals that bring water from the Owens Valley to Los Angeles. The completion of the aqueduct was a major engineering feat and allowed for the growth of Los Angeles into a major metropolitan area.

3. The first U.S. patent for a typewriter was issued on December 23, 1829, to William Burt of Detroit, Michigan. While this may not seem directly related to California, the state has a long history of technological innovation and was home to many tech companies during the dot-com boom.

4. On December 23, 1879, the California State Capitol building in Sacramento was destroyed in a fire. The building was reconstructed and completed in 1884 and still serves as California's State Capitol today.

5. The movie "It's a Wonderful Life" premiered in New York on December 20, 1946, but it was released widely in California on December 23 of that year. The movie has since become a holiday classic and is regularly shown on television during the Christmas season.