The Straits of the Dardenelles
During World War I, Germany did in fact control the Dardanelles Strait, if only through its ally, the Ottoman Empire. Control of this narrow strip of water and surrounding areas was crucial for Germany and the Ottoman Empire in their attempt to prevent a link-up between the Allies through the heart of the Ottoman Empire itself.
narrow or broad
There are a great many countries that were never conquered by the Ottoman Turks. Russia, China, Australia, and many more. You might narrow this down a bit by asking what country did the Ottoman Turks attempt to conquer, unsuccessfully. That was Austria.
In 1915, during World War I, Allied forces invaded a small peninsula located in the Ottoman Empire and called Gallipoli. Located at the western tip of the Dardanelles Strait, the first narrow waterway allowing access to the Black Sea from the Mediterranean, Gallipoli was tenaciously defended by Ottoman (or, Turkish) defenders, who succeeded in blocking the Allied attempt to penetrate inland via their Gallipoli beachhead.
There are a great many countries that were never conquered by the Ottoman Turks. Russia, China, Australia, and many more. You might narrow this down a bit by asking what country did the Ottoman Turks attempt to conquer, unsuccessfully. That was Austria.
When in a narrow channel
Panama
Panama
panana
Panama
Panama.
Panama