Istanbul is the largest city in Europe, and one of the five largest cities in the world, with a population of almost 13 million people. It's incredible, therefore, to think that it took until 2009 for someone to spot the ancient and long-lost Roman city of Bathonea just 20 kilometres away, amid a historical landscape eight kilometres wide, dating from the classical era back into the mists of prehistory.
The site - first inhabited by humans 15 millennia ago - has been hidden in plain view, beneath farm land, on the banks of Lake Küçükçekmece, a small inlet west of Istanbul. The remains of Bathonea may be partially submerged in the waters. A reported minaret in the middle of the lake is believed to be the remains of Bathonea's lighthouse. If this is verified, it'll represent one of just three Roman lighthouses known to have existed in the eastern Mediterranean, next to those at Alexandria and Patara.