The day is mostly celebrated in the United States and is associated with Mexican culture.
Cinco de Mayo celebrations began in California where have been observed annually since 1863.
Cinco de Mayo is often mistaken for Mexico's Independence Day which is celebrated on September 16th. It was in 1810 Miguel Hildago, a Spanish Catholic priest gave his famous speech Grito de Dolores and initiated Mexico's revolt that lasted till 1821 when Mexico obtained its independence from Spain.