What They Found Will Change History Forever. The city of Heracleion was engulfed underwater 1500 years ago. This grand city had been mentioned by the Greek writer Herodotus, the 5th-century BC historian. When French marine archaeologist Franck Goddio stumbled upon some relics, it led them to one of the greatest finds of the 21st century; a city underwater. Read the Sunny Skyz article.