Just months after the attack on Pearl Harbor when the US declared war on Japan the sirens blared in southern California on February 24th, 1942 at around 10:30pm. Becoming common, people took to the streets to see what was going on and to witness if it was another false alarm. Nobody could have ever possibly guessed what they were about to see in a million years.
The coast guard and US Navy got prepared for a possible attack on the sunny shores of California, preparing their anti-aircraft weapons, Navy ships, and Air force after getting word of a single or multiple aircraft heading for the coast. When the object became visible and was confirmed to not be a private or commercial aircraft it became apparent that this craft was unlike anything they had seen before. It was huge and could silently hover and the move at will. The Navy and Coast Guard got the go ahead from the Secretary of the Navy Frank Knox and began firing at the Unidentified flying object in the sky around 3:00am on the morning of the 25th.
From the beginning of the attack until the early morning around 4:15am the Military fired over 1400 rounds of 12.8 pound anti-aircraft artillery at the UFO. The object kept moving from Santa Monica to Long Beach and seemed to have no damage done from the barrage of shells that were fired at the UFO.
There were thousands of witnesses including very credible reporters from every newspaper in the area that saw the UFO up close and personal. Later after all was calm the US Military reported that it must have been just a weather balloon. The extremely odd thing about that is all of the witnesses stated that it was clearly not a weather balloon, but a large circular object that was being maneuvered in ways that no balloon or even aircraft of that time could have. Also, after firing 1400 rounds of shells at the UFO it continued to move along unscathed. If our military couldn't have brought down a weather balloon then we never would have won the war or any war for that matter.
With all of the evidence in the Battle of LA case it clearly points to nothing man-made either US or Japanese. With all of the witnesses that saw the UFO and the unbelievable amount of artillery fired at the object without even touching it it's very clear that we were dealing with one of the first multi person UFO sightings in the USA.