In the 2011 fictional film Battle: Los Angeles, aliens invade the modern city. But in the opinion of some there actually was an invasion, or at least a prelude to one, sixty years earlier. The entire west coast was tense then, just two months out from the bombing at Pearl Harbor. All preparations that could be taken against air attacks — blackouts, warning sirens, fighter squadrons on alert — were taken, and the city lived in continual readiness for the worst, which seemingly arrived one night.

On this day, February 24, in 1942, air raid warnings sounded over L.A. during the evening rush hour, 7:18 pm. No planes ever came, however, and the all-clear signal was given three hours later. Most of the residents went to sleep, but shortly after 2:00 AM, anti-aircraft batteries were warned that radar picked up an unidentified bogey moving towards the city. A red balloon was fired at over Long Beach, which started searchlights and the accompanying blind anti-aircraft artillery barrage.

Nothing was ever shot down over Los Angeles, and no invasion force terrestrial or otherwise ever materialized. Most of the imagined aircraft were really just exploding shells illuminated by the searchlights. But many soldiers and civilians alike reported a giant, hovering aircraft lit up by search beams and taking heavy fire seemingly without any effect. A photograph published in the following days supported the UFO story, but turned out to be heavily retouched – the skyline was darkened, while the lights and lens flare were lightened up.