For centuries, the Maya ruins -- the remnants of an ancient empire -- have dared outsiders to unlock their secrets.
Two years ago, a controversial movie director decided to take that dare. The result is Mel Gibson's new film, "Apocalypto," which opens on Dec. 8.
One of the most physically harrowing shoots in Hollywood history began because Gibson decided it would be fun to make a "chase" movie.
"My first instinct," Gibson said to ABC's Diane Sawyer, "was, 'Wow. Chase movies, you know? What kind of chases? Let me see: There's car chases. There's plane, bus, boats.'"
Gibson ultimately decided nothing could match the heart-pounding terror of a man literally running for his life.
His hero in "Apocalypto" is named Jaguar Paw, after the sacred Mayan jaguar with green eyes.
The actor who brought Jaguar Paw to life is Rudy Youngblood, a 25-year-old Native American who had never been in a movie before, and whom Gibson describes as an "everyman kind of guy."
In the movie, Jaguar Paw is a young Maya villager fleeing from bloodthirsty tribal rulers.
The Maya of the late 1500's believed that human sacrifice was nourishment for their gods, and planned to kill Jaguar Paw.
After his escape, Jaguar Paw encounters one terrifying peril after another, enduring a kind of odyssey through all our -- and Gibson's -- most primal fears.
In total, "Apocalypto" boasts a cast of 3,000 American Indians, nonactors speaking only Spanish or the native Mayan language, Yucatec.
For eight months, they struggled together through the harsh conditions and blistering heat.
By the time the movie was over, Gibson says, the actors all became indestructible warriors.
"There was a lot at stake for these guys," he said, "but they all pulled it off. It was great."
Gibson's guide into the history of these legendary cities was Richard Hansen, a professor of anthropology at Idaho State University.
"One of the great things about 'Apocalypto,'" Hansen said, is that "it brings [the ancient world] to life here. It's an opportunity to see a city like this being brought to our conception of what it would look like originally."
Gibson explained the film's title to Sawyer:
"'Apocalypto.'… It's Greek, of course. It just means a new beginning or an unveiling -- a revelation."
When asked whether it related to the biblical revelation, Gibson said: "Everything has a beginning and an end, and all civilizations have operated like that."
Gibson says the movie has universal appeal because on a basic level, it addresses fear.
When asked whose fears we see in the film, Gibson said: "Boy, they're most people's. I think a lot of them are mine."
"People like scary stories," he said. "There's a fascination with fear themes, and we want to face those things in a weird, subconscious way."
Gibson knows all about facing fears: He made his name taking chances -- as an actor, and then as a director.
No one in Hollywood thought "Braveheart" would be an Oscar-winning commercial success, and then he spent $30 million of his own money to bring "The Passion of the Christ" to the big screen.
The film has earned almost $1 billion worldwide.
When it comes to risk, though, Gibson has made it clear that nothing in his career ever matches the terror he faces every day in his battle against alcohol and lifelong addiction.
Four months ago, after a long period of sobriety, Gibson fell back.