Bosphorus / Turkish Straits
artifactNations & Geopolitics
One narrow strip of water, controlled by one country, can bottle up Russia's navy and the world's grain.
Who they are
The Bosphorus, the Turkish Straits linking the Black Sea to the Mediterranean.
What they do
The only sea passage in or out of the Black Sea, controlled by Turkey.
How it works
It's just 0.7km wide at its narrowest, and under the 1936 Montreux Convention Turkey controls which warships pass — with total discretion in wartime. A proposed 45km Kanal Istanbul bypass would sidestep those rules. After 2022 Turkey used Montreux to restrict warship transits.
Why it matters
Whoever controls it controls Russia's Black Sea Fleet access, Ukrainian grain exports, and NATO's ability to reinforce Black Sea states — enormous leverage in one chokepoint.
The engine's record — word for word
Only passage between Black Sea and Mediterranean. 0.7km wide at narrowest. Governed by Montreux Convention (1936): Turkey controls warship transit. In wartime, Ankara has total unilateral discretion. Kanal Istanbul (45km bypass) would create non-Montreux waterway. Controls Russian Black Sea Fleet access, Ukrainian grain exports, NATO reinforcement of Black Sea states. Post-2022: Turkey invoked Montreux to restrict warship transit.
Follow the trail
Walk this on the live map →