Cinco de Mayo means "the fifth of May" in Spanish. It's a special celebration, devoted to commemorate the Mexican Army's unlikely victory over French forces at the Battle of Puebla on May 5, 1862, under the leadership of General Ignacio Zaragoza. Cinco de Mayo is usually confused with the Mexico's Independence Day, which is considered the main holiday in the country and is celebrated on the 16th of September.

Cinco de Mayo is based on an important historical event. Late in 1861, a well-armed French fleet stormed Veracruz, landing a large French force and driving President Juárez and his government into retreat. The 6,000-strong French army attacked the much smaller and poorly equipped Mexican army of 2,000.Yet, on May 5, 1862, the Mexicans managed to decisively crush the French army, then considered "the premier army in the world" and national heroes.

Active celebrations are held on this day in Mexico and the USA. A large celebration takes place at the White House, as well as large military parades in Mexico. Different states also have special traditions of celebrating Cinco de Mayo. The day is also celebrated worldwide. It's a tradition to wear Mexican national clothes, serve Mexican cuisine and drinks and play Mexican folk music. Special Mexican festivals take place in England, Canada, New Zealand, Japan and other countries. It's always associated with Latin American culture in general.

More Info: en.wikipedia.org