Sunken 4th Century Basilica | Secrets of the Dead | PBS Uncover the sunken remains of a 4th-century basilica in Turkey. Submerged beneath the waters of Lake Iznik for hundreds of years, the church could reveal crucial insights into the early days of Christianity. Join a team of international researchers as they travel back through time—and grapple with Turkey’s many earthquakes which could sink the structure deeper at any moment. #timeline #history #pbs