(Google Earth Placemark)
The Dardanelles and Bosporus Passages
The dividing line between Europe and Asia, the link up between the Mediterranean and the Back Sea, the Bosporus is an ancient valley along a fractured tectonic line. From the Mediterranean Ocean, it runs through the Dardanelles passage to reach the Sea of Marmara, a small interior sea. Then, the narrow Bosporus passage (1 km at its narrowest point) goes through Istanbul to reach the Black Sea.