After confusion swept Los Angeles early on Feb. 25, 1942, the report from Western Defense Command was vague: "Unidentified aircraft were reported in the Los Angeles area."
What was experienced on the ground on that day 74 years ago, however, was very specific. As TIME reported the following week, " Los Angeles citizens crawled out of beds and goggled at the moon. The city had been blacked out. Suddenly, from dozens of Army anti-aircraft posts, searchlights lanced the dark. Orange bursts blossomed in the sky. The city shook with the concussion of ack-ack guns. For almost two hours, except for one 15-minute interval of scary silence, batteries coughed steadily, spewed 1,430 rounds of ammunition into the night."
For residents for whom the memory of Pearl Harbor was fresh, the possibility of an attack—later dubbed the "Battle of Los Angeles"—seemed very real. But the shot-down plane that the L.A. Times reported on was never found, and the Secretary of the Navy announced that the whole thing had been a false alarm, though Army officials maintained that enemy planes had in fact been sighted in the area.
Whatever did cause the air raid procedure to be launched, it's no wonder that the Battle of Los Angeles is also a favorite event for UFO conspiracy theorists.
In fact, it wasn't until years later, in 1947, that the common flying saucer image of a UFO would begin to sweep through American popular culture. But, in the years that followed, the reports poured in. Here are a few of the early images that captured the imaginations of those who wished—or feared—to discover that we Earthlings might not be alone.