In 290 BC, the Egyptian Pharaohs construct one of the Seven Wonders of the Ancient World, the tallest lighthouse ever built: the Lighthouse of Alexandria. In the 14th century, an earthquake toppled her and the tower's remains fell into Alexandria harbor where they were forgotten for centuries. Now, researchers believe they have found the stones from the lighthouse. But others say these can't be her stones because they believe the lighthouse stood in a very different location. Join our deep-water detectives, John Chatterton and Richie Kohler, as they dive in Alexandria for the archaeological ruins that hold the key to solving this ancient mystery.