: Just months after Pearl Harbor, jitters over a Japanese attack led U.S. forces to fire over 1,400 anti-aircraft shells at unidentified objects in the sky over Los Angeles .

: The filmmakers focused on tactical realism, putting actors through a three-week Marine boot camp and using handheld "shaky cam" techniques to mimic real combat footage .

: No enemy aircraft were ever found. The military later attributed the event to a "false alarm" caused by a lost weather balloon and "war nerves" .

Directed by Jonathan Liebesman, the film is a "documentary-style" war movie that depicts an alien invasion through the eyes of a U.S. Marine platoon .

: A group of Marines, led by Staff Sergeant Michael Nantz (Aaron Eckhart), must rescue civilians and destroy an alien command center in a war-torn Los Angeles .

: The incident remains a favorite topic for UFO theorists, who speculate the objects were actually extraterrestrial craft—a theory the 2011 film uses as its core premise . "Mockbuster" Confusion