1. The first commercial oil well in California was drilled on January 28, 1865, in Pico Canyon. The oil discovery led to the formation of the petroleum industry in California, which has played a significant role in the state's economy over the years.

2. On January 28, 1915, a massive earthquake struck the city of Avezzano in Italy, killing over 30,000 people. Many Italian immigrants living in California at the time were deeply affected by the tragedy and organized relief efforts to support their families and communities back in Italy.

3. The famous "Black Dahlia" murder case began on January 28, 1947, when the body of Elizabeth Short was found in a vacant lot in Los Angeles. The unsolved murder has remained a source of fascination for many over the years, and has been the subject of numerous books, movies, and TV shows.

4. On January 28, 1986, the space shuttle Challenger exploded shortly after takeoff, killing all seven crew members on board. One of those crew members was Christa McAuliffe, a high school teacher from Concord, California, who had been selected to participate in NASA's Teacher in Space program.

5. January 28, 2020, marked the first day of the impeachment trial of President Donald Trump in the United States Senate. The impeachment proceedings were seen as a historic moment in American politics, and sparked heated debates and discussions across the country, including in California.