[Ghoulish Delight]

Contrary to popular belief, Cinco de Mayo is not Mexican Independence Day, and is not even a federally recognized holiday in Mexico.

It's the celebration of an isolated battle, in the state of Puebla, in which Meixcan troops, fewer in number and less trained, defeated occupying French forces. It slowed the French, who were trying to take over Mexico, although the French did eventually succeed in occupying Mexico City for 5 years until the US forced the installed Emperor Maxamilian out.

It's possible that the Battle of Pueblo was tangentially instrumental to the Union's victory in the Civil War. The Confederates were looking for an ally, and the French, likely keen on the US splitting up, would have been a good candidate. The unexpected difficulty they had in Pueblo may have prevented them from lending the resources the South could have used to hold their ground and succeed on secession.