The Battle of Los Angeles:

On the night of February 24, 1942, Los Angeles was awoken by air raid sirens. The Coast Guard had began sighting incoming unidentified air craft not long after 11PM. Search lamps were trained on the object(s?), and round after round of anti-aircraft artillery were fired. Although thousands witnessed the unidentified craft, the military failed to bring down a single thing.

"At 3:16 AM the 37th Coast Guard Artillery Brigade opened fire while the target was over Culver City. With the city lights all snuffed for the blackout, the barrage of AA shells was the center of attention. The firing continued intermittently through the night until the blackout lifted at 7:21 AM."

The next morning the Los Angeles Times printed this story:

This is an interesting article on The Battle of Los Angeles:
Here is another one.
...And another.
A bunch of news paper articles about The Battle of LA

This happened not too long after Pearl Harbor was bombed, and America was ripe with fear.
Was this enemy aircraft? A 'false flag' style terrorizing? A gigantic blunder, with mass delusions? Was it alien? Who knows.