Fun fact: In one of the novelizations of Independence Day, Mecca gets obliterated by a City Destroyer (the 15-mile-wide ships), and the climax is about stopping that same City Destroyer from doing the same to Jerusalem--and because this is happening at the same time as the Battle of Area 51 in the movie, the aliens' force fields are down, and humans are able to succeed.

108 cities were still destroyed, though--36 ships attacking three times each, with the fourth wave about to begin. The Area 51 ship was originally meant to destroy San Diego in that fourth wave.