1. The California Gold Rush officially ended on December 6, 1852, when the state government declared that it was no longer necessary to bring gold dust to the mint to be exchanged for coins. This marked the final stage of one of the most significant events in California's history, which brought thousands of settlers to the state and transformed its economy.

2. On December 6, 1917, the worst train accident in California history occurred when two trains collided head-on near Santa Clara. The accident killed 22 people and injured more than 130 others, many of whom were soldiers returning from World War I.

3. In 1969, a group of Native American activists occupied Alcatraz Island in San Francisco Bay, claiming it as Indian land. The occupation lasted for over a year and brought national attention to the issue of Native American rights. On December 6, 1970, the federal government announced that it was willing to negotiate with the occupiers, marking a significant turning point in the standoff.

4. The first-ever streetlights in the United States were lit in San Diego on December 6, 1887. The city had been using gas lamps for several years, but the new electric lights were much brighter and more reliable. Today, San Diego is known for its innovative and sustainable approach to street lighting.

5. On December 6, 1947, the Hughes H-4 Hercules aircraft (more commonly known as the "Spruce Goose") made its first and only flight in Long Beach. The massive airplane, designed by billionaire Howard Hughes, was the largest wooden airplane ever built and remains a symbol of innovation and daring engineering.