Over the years, Cinco de Mayo has almost become an unofficial national holiday here in the U.S., as an opportunity to honor Mexican culture and, um, party.
In Mexico, Cinco de Mayo celebrates the Battle of Puebla, a decisive victory of the Mexican army over the French army and is an important national holiday -- not as important as Independence Day, though.
So why is Cinco de Mayo now so big in the U.S.?
Pablo Piccato, director of the Institute of Latin American Studies at Columbia University, says, 'It represents the date in which Mexicans were able to fight and defeat an invading army, so it's very important for this spirit of nationalism.'
For most people in America, though, tonight will mostly be a good reason to party.