Watch Swallowed By The Sea: Ancient Egypt's Greatest Lost City (2014) : Full Movie Online Free We all know about Alexandria, one of the greatest cities of the classical world, with its great Library and fabled Lighthouse. But Heracleion? A great port and religious centre at the mouth of the Nile, it was mentioned by the likes of Herodotus, but at some point it vanished, and its location became unknown.