The Turkish Straits are two internationally significant waterways in northwestern Turkey. The straits create a series of international passages that connect the Aegean and Mediterranean seas to the Black Sea. They consist of the Dardanelles and the Bosphorus. The straits are on opposite ends of the Sea of Marmara. The straits and the Sea of Marmara are part of the sovereign sea territory of Turkey and subject to the regime of internal waters. Located in the western part of the landmass of Eurasia, the Turkish Straits are conventionally considered the boundary between the continents of Europe and Asia, as well as the dividing line between European Turkey and Asian Turkey. Owing to their strategic importance in international commerce, politics, and warfare, the Turkish Straits have played a significant role in European and world history. Since 1936, they have been governed in accordance with the Montreux Convention.
The Bosphorus, about long and only wide, connects the Sea of Marmara with the Black Sea in the north. It runs through the city ofIstanbul, making it a city located on two continents. It is crossed by three suspension bridges, and two underwater tunnels. There are plans for further crossings being debated at various stages.
The Straits have been of urgent maritime strategic importance since the Trojan War was fought near the Aegean entrance. In the declining days of the Ottoman Empire the "Straits Question" involved the diplomats of Europe and the Ottoman Empire. By the terms of the London Straits Convention concluded on July 13, 1841, between the Great Powers of EuropeRussia, the United Kingdom, France, Austria and Prussiathe "ancient rule" of the Ottoman Empire was re-established by closing the Turkish straits to all warships whatsoever, barring those of the sultan's allies during wartime. The treaty is one in a series dealing with access to the Bosphorus, the Sea of Marmara, and the Dardanelles. It evolved from the secret 1833 Treaty of Hünkâr İskelesi, in which the Ottoman Empire guaranteed exclusive use of the Straits to "Black Sea Powers" warships in the case of a general war. The modern treaty controlling relations is the 1936 Montreux Convention Regarding the Regime of the Turkish Straits, which is still in force. It gives the Republic of Turkey control over warships entering the straits but guarantees the free passage of civilian vessels in peacetime.