April 21 - 1836 - The Battle of San Jacinto
As far as world changing battles go, the Battle of San Jacinto was not a grand clash of epic armies. Instead, a few hundred Texans overwhelmed a force of over 1,000 Mexican troops in about 18 minutes. The Battle of San Jacinto did, however, ensure that Texas would become independent from Mexico, as it ended the Texas Revolution. The battle was the only major engagement between a Mexican and a Texan army since the significant victory by Mexican President Jose Santa Anna de Lopez at the Alamo. Texan General Sam Houston had been organizing a significant retreat in the meantime, as he needed some way to arm, train, and gather his forces. Eventually, Santa Anna reached Houston's army near Buffalo Bayou. Santa Anna then camped and waited for reinforcements. Strangely, he picked a terrible, enclosed location near a wooded marsh. So when Santa Anna allowed his troops to rest on the afternoon of April 21, his forces were overwhelmed. After being captured the next day, Santa Anna had no choice but to agree to Texan independence.