Stonehenge is the most famous prehistoric monument in history with origins that have baffled historians for centuries. Armed with cutting-edge technology, experts reveal celestial secrets that could finally unlock the mystery of this ancient wonder. This is a mashup of S08E06 "Secrets of Seahenge" and S02E05 "Ghosts of Stonehenge."

Ancient civilizations buried underwater for centuries hold answers to a mysterious and unexplained past; using cutting-edge archaeological methods and pioneering radar technology, experts investigate these sunken empires and the secrets of their remains. This is a mashup of S08E07 "Secrets of the Sunken Empire" (Pavlopetri) and S07E08 "Egypt's Sunken Treasures."