History's Greatest Mysteries: Season 4, Episode 10

4 - 10: The Puzzling Pyramids of Egypt

Awe-inspiring and mysterious, the pyramids of Egypt are among the most significant wonders of the ancient world. More than 4,000 years old, they are among the most celebrated architectural marvels in the world. But no one fully understands how they were built, or why. Can we ever decipher the true purpose of Egypt's astonishing pyramids?