Armed with information from Ephialtes (Andrew Tiernan), a Greek traitor, the Persians were en route to victory - and Leonidas knew it. Would he and his men finish the battle, in which they would surely die, or would they retreat? Would he return home to his wife Gorgo (Lena Heady), or would she never see him again?

In this story behind the movie, visit Thermopylae where the famous battle took place. See drawings of the narrow pass, as it existed in the fifth century B.C., and hear the story from the chronicles of Herodotus. Visit Marathon, where a small number of Greeks defeated the Persians in the summer of 490 B.C., and virtually operate a Greek ship of war - the trireme - as it attempts to ram its opponents.