What part did Istanbul play in the cold war? Whose side were they on, and was it a significant place during the cold war?

I'm not sure how to answer this . Istanbul is on the Bosphorus Strait which is a very strategic international waterway connecting the Black Sea ultimately to the Mediterranean sea. It also sits on the geographic border of Europe and Asia.

Turkey itself became a focal point in the Cold War arms race and was a front line nation in the containment policy.Truman invested heavily in preventing Greece and Turkey from Communism . Turkey became an active member of NATO.

The arms race came to a head in 1962's Cuban Missile Crisis . As part of the compromise to ease tensions JFK agreed that Turkey would not base a US nuclear deterrent in the country .