Battle of Los Angeles 1942

The Battle of Los Angeles, also known as The Great Los Angeles Air Raid, is the name given by contemporary sources to the rumored enemy attack and subsequent anti-aircraft artillery barrage which took place from late February 24 to early February 25, 1942 over Los Angeles, California.

The incident occurred less than three months after the United States entered World War II as a result of the Japanese Imperial Navy's attack on Pearl Harbor, and one day after the Bombardment of Ellwood on February 23.

Long Beach Independent wrote:
"There is a mysterious reticence about the whole affair and it appears that some form of censorship is trying to halt discussion on the matter."

Some modern-day UFOlogists have suggested the targets were extraterrestrial spacecraft.
When documenting the incident in 1983, the U.S. Office of Air Force History attributed the event to a case of "war nerves" likely triggered by a lost weather balloon and exacerbated by stray flares and shell bursts from adjoining batteries.

They kept firing on the object for a long period of time, and over 1,400 shells was fired that night, but nothing seemed to effect the UFO...
I say UFO because to this day it is still unidentified.