Fait mathématique: 1504 is the number of anisohedral 21-iamonds.
Culture générale: 1504 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Date historique: February 12th is the day in 1817 that an Argentine/Chilean patriotic army, after crossing the Andes, defeats Spanish troops on the Battle of Chacabuco.