1. It wasn’t originally called Independence Day
The essential Fourth of July film almost had very little to do with the Fourth of July. At first, the studio wasn’t sure that the movie should lay claim to such a coveted title, which might work better on an Oscar-bait period drama about, well, Independence Day.
To convince the studio otherwise, the filmmakers added the “Today we celebrate our Independence Day!” line into Bill Pullman’s speech at the last minute, hoping that his stirring performance would convince the suits to see it their way.
Obviously, it worked. Fun fact: the other proposed title was Doomsday. Which is a considerably less awesome holiday.