The answer is Turkey. The 1936 Montreux Convention establishes it as an International Shipping Lane with Turkey retaining the right to restrict Naval Traffic to Non-Black Sea nations.
Turkey controlled the Dardanelles
Battle of Gallipoli of 1915.
it was the Daranelles xx
The Dardanelles Straight connects the Sea of Marmara to the Eagean Sea and the Bosphorous Straight connects it to the Black Sea
The Dardanelles Straits were the only way out of the Black Sea. In order for Russia to export and import through its Black Sea ports was to be able to send ships through the straits into the Mediterranean. Controlling the Dardanelles would make shipping through them much easier.
Bosporus and the Dardanelles
The Dardanelles/Bosphorus sea route between the Black Sea and the Mediteranean.
Turkey controlled the Dardanelles
Dardanelles
The Dardanelles were known as the Hellespont.
the Bosphorus and Dardanelles sea routes (also known as the Turkish Straights)
Dardanelles - band - was created in 2006.
Dardanelles Operation happened in 1807.