Cinco de Mayo has become a day to celebrate Mexican heritage, especially in the U.S., but historically, the holiday celebrates Mexico's triumph over France.

Cinco de Mayo was first celebrated in the United States in 1863 in Southern California. It's not considered a federal holiday, but became a national holiday in the U.S. in 2005.

Why is Cinco de Mayo often confused with Mexico's Independence Day? Though many might know the lore behind Cinco de Mayo, it is often confused with Mexico's Independence Day, which falls on Sept. 16.

Cinco de Mayo festivities are taking place across the U.S. with music, tacos, tequila and colorful displays of Mexican culture — even if they're not always the most authentic.