May 5th – Cinco de Mayo – Celebrates the victory of the Mexican Army, led by General Ignacio Zaragoza against French forces in the city of Puebla, on May 5, 1862.

Also widely celebrated in the United States. US “celebration” of this Mexican historical event is largely a result of promotions in the US by liquor, beer, and bars/taverns/clubs/restaurants since the 1980s. For many years Cinco de Mayo celebrations in the US promoted Cinco de Mayo as Mexican Independence Day which is actually September 16. Although Mexican citizens feel very proud of the meaning of Cinco de Mayo, it is not a national holiday in Mexico, but it is an official holiday in the State of Puebla where the mentioned battle took place.

More about Cinco de Mayo here.
https://www.eventsloscabos.com/2013/05/cinco-de-mayo/