Just east of the San Francisco Bay Area are the Berkeley Hills Walls–remnants of a massive, stone wall that stretches a distance of over fifty miles, in Season 3, Episode 7, “Marco Polo Discovers America.” #AmericaUnearthed Subscribe for more from America Unearthed and other great The HISTORY Channel shows: Find out more about the show… Continue reading America Unearthed: Ancient Ruins Discovered in California (S3, E7) | Full Episode | History