If it is to the Mediterranean Sea it would be The Bosporus and The Dardanelles Strait's.
Turkey had originally declared war on russia,subsequenly the entente powers doing the same to the ottoman empire.they had gone to war with russia becaus eof the on going threats russia made in their desire to control the Turkish straits.
access to the Mediterranean Sea
There are 5. Russia, Turkey, Kazakhstan, Georgia, and Azerbaijan.
The black sea is not part of any ocean but sits on the boundary of Asia and Europe with turkey on the south coast. There us a very narrow access to the eastern meditteranean sea through the straits of the bosphorus and ultimately there is access to the Atlantic through the straits of gibraltar. Navigational access does mean it is part of the Atlantic though - they are hundreds of miles apart
The Dardanelles and the Bosporus are the strategic straits that divide Turkey between Europe and Asia.
Turkey is the country that is found on two continents, Europe and Asia, and has the Bosporus Strait running through its capital city, Istanbul.
Turkey straddles the Bosphorus Straits, which separate Asia from Europe. Therefore, parts of Turkey are in both.
The Bosporus Strait, and the Dardanelles Strait.
Turkey.
ANSWER Britain and France feared that Russia could overwhelm Turkey and get a foothold in the Mediterranean. The victory of the alliance between France, Britain, Turkey and the Reign of Sardinia, prevented Russia from reach that task. The Straits of Dardanelli and Bosphorus were to be closed to all warships transit unless authorized by the Turkish Government from time to time.
controlled access to the mediterranean sea :)
Turkey controlled the Dardanelles