Wikipedia
Bathonea (Bathoneia, Βαθονεία in Greek) is the name of a long-lost ancient Greek city that was located on the European shore of the sea of Marmara, 20 km west from Istanbul in Turkey.
The ruins of this town, which have always remained visible, were studied extensively in 1930 by the Swiss archeologist Ernest Mamboury, who - based on ancient sources - identified the settlement as the town of Rhegion. In 2009 a new identification has been proposed, with the Hellenistic-Roman city of Bathonea.
At present excavations are conducted under the direction of Dr. Şengül Aydıngün, an associate Professor of the Kocaeli University. The settlement lies 20 kilometres west from Istanbul. Bathonea's site is eight kilometers wide, reaching a small inlet west of Istanbul on the banks of Lake Küçükçekmece. Some remains of this city could be submerged in the waters of this lake. A researcher found a lighthouse in the middle of the lake that could belong to Bathonea. If this is verified, it will be another Roman lighthouses that existed in the eastern Mediterranean, such as that of Alexandria and Patara.