Puerto Vallarta, Mexico - Lots of us have heard of the Mexican holiday Cinco de Mayo, but not everyone knows what it celebrates. It is not, as some believe, Mexico's Independence Day. The festivities that occur on the fifth day of May commemorate a battle that was fought almost 50 years after Mexico declared its independence from Spain.

Cinco de Mayo celebrates Mexico's independence, but it is not Independence Day. Mexico asserted its independence from Spain on September 16, 1810. The festivities on May 5 are about another battle for independence - a battle fought against the French in 1862.

After the 1846 Mexican-American War, in which boundaries were clarified after Texas became the 28th U.S. state, Mexico entered a period of political and financial hardship. The Mexican civil war lasted from 1858 to 1861 and left Mexico without a stable support structure. To supplement a deflated economy, Mexico borrowed a great deal of money from other countries. Among those countries were England, Spain and France.

In 1862, all three European powers came to collect. Their navies arrived in Mexico to demand payment and land to settle the debts, but Mexico offered vouchers instead, essentially asking for more time. England and Spain accepted and went home; France invaded, seeking total control of Mexico. Under Napoleon III, French troops began at the shore and tried to make their way to Mexico City. Before they could get to the capital, they were stopped at the state of Puebla, where a major battle took place on May 5, 1862: La Batalla de Puebla.

Outnumbered and outarmed, the Mexican soldiers at Puebla, under the command of General Ignacio Zaragoza Seguin, managed to defeat the French forces. Ultimately, the Mexican victory at Puebla only delayed the French invasion of Mexico City, and a year later, the French occupied Mexico.

But the Mexican men who fought at Puebla nonetheless defied the odds to defend its independence. Cinco de Mayo celebrates that bravery and determination, and commemorates Mexico's fight to ward off imperialist forces.

The city of Puebla holds a big annual celebration on the anniversary of the battle. But in most of Mexico, Cinco de Mayo is not really celebrated. The real celebration takes place on Independence Day, the Sixteenth of September (or Diez y Seis de Septiembre), when everybody celebrates similar to the way the Fourth of July is celebrated in the U.S., with feasting, fireworks and parades dedicated to celebrating Mexico's freedom from European external powers.