It may be Turkey to you, but it will always be Byzantium to me.
And what if you made a date to meet someone in upper volta (hint, bring some consonants, if you're planning on visiting the capital), or in the aftershave hub of Asia, burma? Much room for hilarious misunderstanding.
I'll be in the corner, nursing my Mumbai Sapphire gin.
c_b: I had thought as well that Leningrad was called Stalingrad at one point. But when I looked it up, it seems it was actually Volgograd that made the change to Stalingrad and back.
The one that remains mysterious is Königsberg, famous in its day for Euler's celebrated "7 bridges" problem. This eventually became Kaliningrad; given its East Prussian location, one might have expected it to be one of the first to regain its original name. In fact, if Wikipedia is to be believed, it was briefly Russified as Kyonigsberg (Кёниг�?берг), before being renamed to Kaliningrad (Калинингра�?д).
I had assumed until recently that it belonged to one of the Baltic republics, but in fact it remains a Russian exclave, the so-called Kaliningrad oblast. A reminder of its strategic importance during the Cold War as one of the westernmost territories of the Soviet Union came as recently as July of this year, when Russian First Deputy Prime Minister Sergei Ivanov declared that if US-controlled missile defense systems were deployed in Poland that nuclear weapons may be deployed in Kaliningrad.