It celebrates the Battle of
Puebla, when the Mexicans kicked some
French ass.
Incidentally, it was also the day
Napoleon died, which prompted
Alessandro Manzoni to write a massive Ode to the great men.
Italian kids are usually forced to learn it by heart at school: if you want to force flashback on a bunch of unsuspecting
Italians just shout at the top of your lungs "
Ei fu, siccome immobile !" - they will not be able to resist, in this respect we are much like the
cartoon characters in the
Who framed Roger Rabbit movie.