The Battle of Los Angeles

February 25, 1942 - At around 3 o'clock in the morning, residents of Los Angeles were rattled out of bed by the loud thumps of anti-aircraft guns lobbing 12-pound shells into the sky.

Super bright spotlights criss-crossed above the blacked-out city and converged on a mysterious and massive object that drifted across Santa Monica then hovered over the MGM Studios in Culver City.

Here's an eerie description from the LA Times:

The fire seemed to burst in rings all around the target. But the eager watchers, shivering in the early morning cold, weren't rewarded by the sight of a falling plane. Nor were there any bombs dropped. "Maybe it's just a test," someone remarked. "Test, hell!" was the answer. "You don't throw that much metal in the air unless you're fixing on knocking something down." Still the firing continued, muttering angrily off toward the west like a distant thunderstorm. The targeted object inched along high, flanked by the cherry red explosions. And the householders shivered in their robes, their faces set, watching the awesome scene.

All kinds of shrapnel and unexploded ordnance rained down on the city, causing lots of damage. 5 people died. After about an hour of getting shot at, the object leisurely made its way down to Long Beach and disappeared over the Pacific.

The days after were filled with all kinds of theories about what had happened, but it remains a mystery.