If you don't remember your Texas history, or are a transplant, in 1836 the Alamo was the site of a pivotal moment in the history of the Texas Revolution where 250 or so Texian and Tejano defenders held off an estimated 1,500 Mexican soldiers for 13 days.
The garrison eventually fell after being overwhelmed by a full siege on March 6. Nearly all of the defenders of the mission were killed, with the exception being an estimated 20 women and children.
The perceived cruelty of Mexican General Antonio Lopez de Santa Anna inspired others living in the new republic, which had just declared it's independence from Mexico four days before, to join the Texian Army.
Santa Anna would be defeated a few weeks later at the Battle of San Jacinto, when the Texian Army, many of whom yelled the now famous phrases "Remember the Alamo and Remember Goliad," surprised and overran the Mexican Army near Lynchburg Ferry during a surprise attack in the middle of the afternoon.
The Mexican Army, many of whom were having a siesta, were largely slaughtered after being caught off guard. More than 700 Mexican soldiers were killed and another 700 or so taken captive in the 18-minute battle. Only nine Texians were said to have died in the attack.
With Santa Anna's capture and signing of the Treaty of Velasco, the Mexican Army was forced to withdraw from Texas.
As explained on thealamo.org, "people worldwide continue to remember the Alamo as a heroic struggle against impossible odds — a place where men made the ultimate sacrifice for freedom. For this reason, the Alamo remains hallowed ground and the Shrine of Texas Liberty."
In 2013, a ceremony marking the 177th anniversary of the battle for Texas independence took on added significance because of Lt. Col. William Barret Travis' famed "Victory or Death" letter being temporarily put on display in the shrine.
The fragile, fading letter was written by the 26-year-old Travis as some 1,500 Mexican forces prepared to lay siege to the mission-fortress. His plea for reinforcements to bolster his badly outnumbered rebel Texans failed to prevent their deaths nearly two weeks later on March 6, 1836.