Bosphorus is a natural strait connecting the Black Sea to the Sea of Marmara, thus being a very strategic waterway. It was a river in the valley during the Tertiary period of the continents, which was drowned by the sea at the end of this period. It's length is 32 kilometers (20 miles) in the north to south direction, width varies between 730-3300 meters (800-3600 yards), and depth is between 30-120 meters (100-395 feet). Bosphorus strait separates the European part from the Asian part of Istanbul. The surface current flows always from north to south; however, a strong countercurrent under the surface creates swirls and eddies.
Bosphorus comes from a Thracian word which means "passage of the cow", deriving from the legend of Io who was one of many lovers of
Hera, Zeus' wife, suspected her husband being involved in a love affair with Io, Zeus converted Io in a small cow and tried to send her away from Hera's rage. She (the cow) swam
across the strait but Hera discovered it and she sent big flies after the cow to bite and disturb her all the time, ending Io in the
Aegean Sea (thus named
Bosphorus in Turkish is known as Bogazici, meaning "inner strait". Since the ancient times it held always an important role because of its strategic location, being the only passage from the
Black Sea into the
Mediterranean, along with the
Dardanelles strait. Especially during the Cold War, the straits were crucial for Soviet navy.
Bosphorus is a very busy waterway with many ships and oil tankers going through it, as well as local fishing and ferries go to the Asian side back and forth. Around 48.000 ships pass through this strait annually, three times denser than the Suez Canal traffic and four times denser than the Panama Canal. Approximately 55 million tones of oil are shipped through the strait each year.
There are three suspension bridges on the Bosphorus connecting Europe to Asia (or vice versa). The first one is known as "Bosphorus Bridge" and was opened on 29th October 1973 between Beylerbeyi and Ortakoy neighborhoods. This bridge's name was changed into "Martyrs of July 15th" dedicated to the victims of the coup attemp on 15th of July 2016. It's 1074 meters (1175 yards) long between two pillars, has 6 lanes, 165 meters (540 feet) height of piers. The second one is known as "Fatih Sultan Mehmet Bridge" (or FSM Bridge shortly) and was opened in 3rd July 1988 between Anadolu Hisari and Rumeli Hisari neighborhoods. This one is 1090 meters (1192 yards) long, has 8 lanes, and is 65 meters high from the water surface. The FSM bridge is a part of TEM highway (Trans European Motorway) between Ankara and Edirne provinces. The third one is known as "Yavuz Sultan Selim Bridge" (or YSS Bridge shortly) and was opened in 26th of August 2016 between Garipce and Poyrazkoy neighborhoods along the shores of the strait. It's one of the longest and highest suspension bridges in the World; 1408 meters (1540 yards) long between 322 meters-high pillars, is 59 meters (65 yards) wide with 8 lanes for motor vehicles + 2 lanes for trains. A new highway is built on both sides of the 3rd bridge for intercontinental trade and commuter traffic. All three bridges are tolled which is paid during the passage to the Asian direction only. On the suspension bridges only vehicles with electronic pass system (called OGS or HGS) are accepted, no cash. No bicycles nor pedestrian traffic is allowed on them.
The tunnel between Uskudar and Yenikapi neighborhoods was put into service in October 2013. It's a big project constructed by Japanese companies, which is delayed for 4 years due to technical reasons and archaeological findings. This tunnel connects only railways / subway between Europe and Asia, not motor vehicles. Another one under the water, a two-level and 5,4 kilometers (3,3 miles) long tunnel runs between Kazlicesme neighborhood in Europe and Goztepe neighborhood in Asia. This project is called "Eurasia tunnel" and was opened in December 2016, used by cars and minibuses only, no motorbikes nor heavy traffic or pedestrians are allowed. More tunnels under the sea are planned in the future.
Bosphorus is one of the most popular areas of Istanbul for its inhabitants, especially during Summer for its
climate. Its shores are lined with fine neighborhoods, Ottoman palaces, fortresses, old wooden villas, hotels, parks and gardens, restaurants, cafeterias, and so on.
Some of the interesting neighborhoods on the Bosphorus are: Besiktas,
Ortaköy, Arnavutköy, Bebek, Rumelihisar, Emirgan, Tarabya, Yeniköy, Istinye, Sariyer, Üsküdar, Kanlica, Beykoz, Anadoluhisar, Beylerbeyi, Cengelköy, and many others. Best way to see these sites would be taking a nice boat trip along the Bosphorus.
Click here for high resolution photo gallery of the Bosphorus.