Christianity evolves in unique ways in Ethiopia's ancient underground engineering marvels and remote, cliffhanging caves; emperors tombs; subterranean cathedrals; the Queen of Sheba's buried palace; possible site of the Ark of the Covenant.

Host Don Wildman explores ancient structures buried beneath the desert sands of Egypt and the streets of Cairo, examines how these engineering marvels survived invasions, and discovers a tomb filled with 2,000-year-old mummies. Also examined: the Book of the Dead and a step pyramid built a century before the Giza pyramids.