December 8, 2006—Mel Gibson's new film Apocalypto, released in theaters today, recounts the mysterious decline of the Maya Empire through the eyes of an unfortunate youth selected for mass ritual sacrifice.

Scientists are still baffled by what caused the Maya—one of the ancient world's greatest civilizations—to begin abandoning entire cities starting around 800 B.C. (Related map: Maya Cities on Mexico's Yucatán Peninsula.)

But experts have pieced together much of what the Maya were like at the height of their influence—and anthropologists say it's a far cry from the depiction in the film. (Related photos: what the Maya Empire looked like.)

Watch clips from Apocalypto—then hear Maya expert Zachary Hruby explain how the movie's grisly take on Maya human sacrifice stretches far beyond the truth.