Cinco de Mayo is a holiday that celebrates the date of the Mexican army's victory over France at the Battle of Puebla during the Franco-Mexican War in 1862. It is not Mexican Independence Day, as is commonly misunderstood. The holiday is primarily celebrated in the state of Puebla, where the battle took place, and in the United States as a celebration of Mexican heritage and culture.
In 1861, Mexico was in financial ruin after years of internal strife and was unable to pay its debts to European countries, particularly France. In response, France, under the leadership of Napoleon III, sent a well-armed force to establish a French empire in Mexico. On May 5, 1862, a small, poorly equipped Mexican army defeated the French forces in the Battle of Puebla.
In Mexico, Cinco de Mayo is celebrated with parades, reenactments of the Battle of Puebla, and other festive events. In the United States, it is a time for people to celebrate Mexican culture with parades, parties, music, and traditional Mexican food and drinks.