One of the great pleasures of a visit to Istanbul is a relaxing cruise along the Bosphorus Straits, a narrow waterway that connects the Black Sea to the Sea of Marmara and eventually to the Mediterranean Sea.
Through the Bosphorus (also spelled "Bosporus") must pass all ships bound for Black Sea ports, including those in Bulgaria, Romania, Ukraine, Russia and Georgia. As a result, this narrow waterway is one of the world's busiest shipping channels. It is about 18.6 miles (30 km) long and narrows in parts to less than half a mile wide. It is said to be the narrowest strait in the world open to international navigation.
In addition, the Bosphorus marks the boundary between the continents of Europe and Asia.
But aside from its "official" duties as a commercial shipping lane and continental boundary, the Bosphorus is also the local waterway for Istanbul. Small fishing boats, pleasure craft and racing sculls share the waters. Former palaces, beautiful homes and lively urban areas line its shores.