The faint sound of cannon fire, firsthand accounts, the famous cry, "Remember the Alamo!"
Millions of people come each year to the site of one of the most famous battles in history, where they stand in the mission-turned-fort that, for a while anyway, held off the Mexican army. They read about the fight, see artifacts from the time and are urged to never forget what happened.
Now visitors can also listen to the history of what has become a source of Texas' undying pride.
The Alamo unveiled a 55-minute audio tour in May that gives each listener music, sound effects and perspective from historians, as well as dramatic readings of eyewitness accounts of the 13 days in 1836 that ended with the fall of the Texas-defended Alamo.
The self-guided $5 headset tour takes visitors throughout the grounds of the one-time fort, including the shrine dedicated to those who died — once a church — and the long barrack, now a museum.
Alamo Director David Stewart said some visitors come to the Alamo simply to say they've been there, others are historians who know the story already, and then there is a "huge group that is really interested in what happened."
"The audio tour gives them the opportunity to live through the experience," he said.
The audio tour also offers trivia a visitor might not otherwise learn. For example, that the bump on the top of the Alamo church that distinguishes its famous facade was added in later renovations.
The Alamo gets 2.5 million visitors a year and is the most visited tourist site in Texas, Stewart said. But there is no tour of the grounds, just a talk given in the courtyard every half-hour. Stewart said the audio tour lets tourists learn about the Alamo as they stroll through it, which is a richer experience than sitting through a lecture.
"If you're on the audio tour, you're hearing the same story and standing in the place where it happened," he said. "You have the experience of standing where Davy Crockett died or where the north wall was. It becomes more personal to you rather than trying to visualize it."
Stewart said he hopes the audio tour will entice previous visitors to return. He said a shorter version of the tour for kids and schools is also in the works.
The tour was produced by Discovery Audio in cooperation with the Daughters of the Republic of Texas, which has maintained the Alamo since 1905. Discovery Audio also produced the popular audio tours at Pearl Harbor, Alcatraz and other famed locales.
So far, visitors say they like the tale that's being told to them.
"When I travel I always take the audio tours," said Marty Stone, 37, of Atlanta. "They put some structure to it, otherwise you're just wandering around."
Marletta Dalton, 51, said the audio tour made the history of the Alamo come to life.
"There's more reality to it in hearing it than reading it," she said. "You can imagine it."