The Black Sea War, occasionally referred to as the Fourth Franco-Turkish War, was a conflict fought primarily between the French Empire and the Turkish Empire between 1957 and 1960, and also came to involve several other states aligned with the two major powers. The Black Sea War is, after the Pacific War, the most destructive traditional war between separate nations ever fought, and after the Pacific War, Chinese Civil War, French Civil War, the armed conflict with the highest death toll and most non-death casualties. The Black Sea War was notable for its involvement of numerous theaters of war and the application of war by proxy, as the Turks and their allies were buffered by American support. The Black Sea War also involved the first presence of nuclear weapons in wartime (although not delivered against military or civilian targets).
The war ended with the defeat and surrender of Turkey and her allies, which led to the formation of the short-lived Arabian Republic and the even shorter-lived Republic of Armenia, Republic of Greece, Republic of Rumania and Slavic Confederacy (later Republic of Serbia and Bosnian Confederacy). Several longer lived states, such as Egypt and Syria, were permanently formed out of the aftermath of the conflict by severing their protectorate status from Turkey, although they remained part of the US-Turkish geopolitical bloc. The war was a major Cold War event and led to the arms race between the United States and French Empire, and also led to the "Unbreakable Friendship" between Turkey and the United States as the first major Cold War bloc was formed, leading to the signing of the NATO Accords in 1966.
Casualty estimates range around 12 million dead and 28 million wounded as a direct result of the fighting, most of them native ethnic peoples of the Balkans or Arabs in the Mesopotamian Valley and the Maghreb.