On June 23, 1921, the Alamitos No. 1 well made history in Signal Hill, California, with the discovery of oil. Although many doubted the area's potential, Shell Oil proved them wrong. When the well blew in, it caused the borehole to collapse, but it was quickly repaired and went on to produce 700,000 barrels over its lifetime. This discovery sparked a major oil boom in Signal Hill, a location named for its use by Native Americans who once sent signals to surrounding hills using smoke and fire. The strike transformed the quiet hill into a bustling oil hub, drawing thousands of prospectors, workers, and companies. By 1923, just two years later, production had soared to 259,000 barrels per day from 300 wells, establishing Signal Hill as one of the most productive oil fields in the country at the time.