1) In 1846, the United States declared war on Mexico, which ultimately resulted in the annexation of California and several other western states. This event marked a significant turning point in California's history, as it led to the establishment of the state as we know it today.

2) On May 3, 1882, the Chinese Exclusion Act was signed into law by President Chester A. Arthur, which effectively banned Chinese immigration to the United States for the next decade. The Act had a profound impact on California, which had a significant Chinese population at the time, and helped shape the state's immigration policies for years to come.

3) In 1933, California was struck by a devastating earthquake that killed over 100 people and caused widespread destruction throughout the state. The quake, which measured 6.4 on the Richter scale, remains one of the most significant natural disasters in California's history.

4) On May 3, 1947, writer and philosopher Ayn Rand gave a speech at the University of Southern California that would later become the basis for her book, "Atlas Shrugged." The work remains a popular and controversial novel to this day, with many readers interpreting it as a critique of socialism and collectivism.

5) In 1978, a series of deadly wildfires broke out throughout the state, destroying thousands of homes and claiming dozens of lives. The fires, which were fuelled by hot, dry winds, remain some of the most devastating in California's history and continue to shape the state's approach to emergency services and disaster response.