Twentieth Century Fox invited a group of scientists to preview this movie, to test their reactions to the "science" used in it. None of the scientists were impressed with what they saw, although most conceded that the movie was enjoyable nonsense.
The river crossing scene was filmed on the U.S.-Mexico border. The extras really were crossing the Rio Grande into Mexico.
The consultation by N.A.S.A. scientists was requested before the filming of this movie, but N.A.S.A. stated that the events in this movie were too ridiculous actually to occur, and denied the request. N.A.S.A. sent a memo out to all of its employees stating that they were not allowed to comment on the likelihood of the events portrayed, but later rescinded this restriction.
On the shot that shows the front of the library, lamps are seen instead of the iconic lions. According to a New York City Public Library employee, the studio didn't want to pay the fee for filming the statues that are a trademark of the institution, and therefore only took advantage of the public area rights of filming.
Has the biggest opening weekend gross for a movie that did not reach number one at the U.S. box-office.
Kirsten Dunst: standing behind Sam, near his elbow, with her sweater pulled up over her nose and mouth, when Sam calls his father to tell him the sewer has backed up into the school.