Cinco de Mayo marks the anniversary of the 1862 victory by Mexican troops over invading French forces at the Battle of Puebla.

While many just celebrate Cinco de Mayo with tacos and margaritas, the day serves as a celebration of the day the Mexican army defeated French forces at the Battle of Puebla in 1862. However, many American restaurants take advantage of the holiday and offer major discounts on food and drinks.

It's actually more popular in the United States than in Mexico. And it may have helped tip the American Civil War in favor of the Union.