Welcome to Istanbul's Bosphorus Strait

The Bosphorus Strait is a natural Strait and an internationally significant waterway located in Istanbul in northwestern Turkiye. In addition to its crucial role as a transit route for commercial ships, the Bosphorus Strait also attracts many tourists wishing to experience life in the sea.

It forms part of the continental boundary between Asia and Europe, and divides Turkey by separating Anatolia from Thrace. It is the world's narrowest strait used for international navigation.

Most of the shores of the Bosporus Strait, except for the area to the north, are heavily settled, with the city of Istanbul's metropolitan population of 17 million inhabitants extending inland from both banks.

The Bosporus Strait and the Dardanelles Strait at the opposite end of the Sea of Marmara are together known as the Turkish Straits.

Sections of the shore of the Bosporus in Istanbul have been reinforced with concrete or rubble and those sections of the Strait prone to deposition are periodically dredged.

GEOGRAPHY

As a maritime waterway, the Bosphorus specifically connects the Black Sea to the Sea of Marmara and thence to the Aegean and Mediterranean seas via the Dardanelles. It also connects various seas along the Eastern Mediterranean, the Balkans, the Near East, and Western Eurasia.

Thus, the Bosporus allows maritime connections from the Black Sea all the way to the Mediterranean Sea and the Atlantic Ocean via Gibraltar, and to the Indian Ocean through the Suez Canal, making it a crucial international waterway, in particular for the passage of goods coming from Russia.

There is one very small island in the Bosporus just off Kuruçeşme.

Now generally known as Galatasaray Island (Galatasaray Adası), this was given to the Armenian architect Sarkis Balyan by Sultan Abdülhamid II in 1880. 

The house he built on it was later demolished and the island became a walled garden and then a water sports centre before being given to the Galatsaray Sports Club, hence its name. However, in the 2010s it was completely overbuilt with nightclubs which were torn down in 2017. It reopened to the public in the summer of 2022. 

EXPLORATION

Before the 20th century it was already known that the Black Sea and the Sea of Marmara flow into each other in a geographic example of "density flow". Then in August 2010, a continuous 'underwater channel' of suspension composition was discovered flowing along the floor of the Bosporus, which would be the sixth largest river on Earth if it were on land. The 2010 team of scientists, led by the University of Leeds, used a robotic "yellow submarine" to observe detailed flows within this "undersea river", scientifically referred to as a submarine channel, for the first time. Submarine channels are similar to land rivers, but they are formed by density currents—underwater flow mixtures of sand, mud and water that are denser than sea water and so sink and flow along the bottom. These channels are the main transport pathway for sediments to the deep sea where they form sedimentary deposits.

VILLAGES

The shores of the Bosporus were once lined with small fishing villages that had grown up since Byzantine times but really came into their own in the 19th century. 

Until the early 20th century most were only accessible by boat (known as caiques) along the Bosporus since there were no coast roads. Today the villages are no more than suburbs of Greater Istanbul but many retain the memory of their original village status in the suffix '-köy (village' to their names. e.g. Ortaköy, Yeniköy, Arnavutköy, Çengelköy and Vaniköy. 

These villages often had distinct identities associated with agriculture: Arnavutköy, for example, was associated with strawberry-growing while Çengelköy was famous for its sweet cucumbers.

HISTORY

As part of the only passage between the Black Sea and the Mediterranean, the Bosporus has always been of great importance from a commercial and military point of view, and it remains strategically important today.

It is a major sea access route for numerous countries, including Russia and Ukraine. Control over it has been an objective of a number of conflicts in modern history, notably the Russo-Turkish War (1877–78), as well as of the attack of the Allied Powers on the Dardanelles during the 1915 Battle of Gallipoli in the course of World War I. 

In 2022 during the Russian invasion of Ukraine the Bosporus' importance as a route by which grain reached the world was thrown into sharp profile.