New discoveries reveal the strange history inside America's most famous structures, and using hi-tech archaeological methods, experts investigate how these modern marvels set new engineering records. This is a mashup of S03E04 "Statue of Liberty: The New Secrets" and S05E02 "Empire State Building: The New Secrets."

New archaeological evidence is revealing the treasures inside some of the world's most mysterious ancient mega tombs; using cutting-edge methods, experts uncover the violent history behind these tombs' construction. This is a mashup of S02E08 "Treasures of the Terracotta Army" and S02E01 "Tut's Buried Secrets."