Genre: Documentary, History, Science
Premise: A camera crew descends hundreds of feet below the streets of major cities -- such as New York, Cairo, London and Tokyo -- to explore the layered remnants of civilizations left buried deep under modern metropolitan centers.
S01, E05 (First Aired: May. 14, 2007)
Snaking quarries, hidden catacombs and mushroom-harvesting tunnels lie beneath the city of Paris.
S01, E10 (First Aired: Jun. 18, 2007)
Freemasons leave behind hints about their role in the rise of America in tunnels beneath Boston and in a water world still intact in Philadelphia.