I don't know how city names get translated into different languages. For those that use the Roman alphabet, frequently the spelling is the same and only the pronunciation differs: Paris (PARE-is vs. Pa-REE), Berlin (Ber-LIN vs. Bare-LEEN). But why is Braunschweig (Germany) translated as Brunswick in English? Or Firenze (Italy) as Florence?
My Mandarin teacher and I had a lot of fun this morning reading a sample weather report and trying to identify the cities, most of which she knew only by their Chinese names. Most often the Chinese is just a phonetic representation of the city, e.g. 芝加哥 (Zhī jiā gē) for Chicago, or 巴塞羅那 (Bā sài luó nà) for Barcelona. Tokyo, however, is 東京 (Dōng jīng), literally "eastern capital" in both Japanese and Mandarin. I had a great time trying to guess the city from the Mandarin name; if I couldn't figure it out from pronunciation alone, she'd give me hints like "It's in Canada," and I could usually figure it out.
The only one I absolutely couldn't get was 德黑蘭 (Dé hēi lán), which my teacher said was a major city in Germany; she thought it was the capital. I suggested both Berlin and Bonn, neither of which was right; finally she asked me just to name a bunch of major cities in Germany because she'd know it if she heard it. "It's a very famous city!" I tried Hamburg, Frankfort, Stuttgart, Düsseldorf, but to no avail. I thought "Dé hēi lán" sounded a bit like Deutschland, but that didn't make any sense; that's not a city.
Finally, we admitted defeat and looked it up online. 德黑蘭 is Tehran.
"Tehran?!" I exclaimed. "That's not in Germany! That's in Iran! Iran is in the Middle East!"
"Oh, that's why I see it in the news all the time."