I found the following Wikipedia page which outlines zillions of European places with various names:

http://en.wikipedia.org/wiki/List_of...ernative_names

I was interested in Siebenbürgen, the German name for Transylvania. I knew the Romanian and Hungarian names, but it looks like there are many other names as well:

Ardeal (variant in Romanian), Ardyalo (variant in Romani), Chiskarpattya - Чискарпаття (Ukrainian), Erdel (variant in Turkish), Erdély (Hungarian), Sedmigradsko - Седмиградско (variant in Bulgarian), Sedmograška (variant in Slovene), Sedmihradsko (Czech), Sedmogradsko - Седмоградско (variant in Bulgarian), Sedmohradsko (Slovak), Siebenbürgen (German), Siedmiogród (Polish), Transilvaania (Estonian), Transilvaneye (variant in Walloon), Transilvania (Finnish, Italian, Romanian, Spanish), Transilvània (Catalan), Transilvânia (Portuguese), Transilvanija (Slovene, Croatian), Transilvanija - Трансилванија (Serbian), Transilvaniya (variant in Romani), Transilvaniya - Трансилвания (variant in Bulgarian), Transilvanja (Maltese), Transsilvania (Latin), Transsilvanien (variant in Danish and German), Transsylvanien (Danish, Swedish), Transsylvanië (Dutch), Transylvania (variant in mediaeval Latin), Transylvánia (variant in Slovak), Transylvanie (French), Transylvánie (variant in Czech), Transylwania (variant in Polish), Transilvanya (Turkish), Urdul (variant in Turkish), Zevenburgen (variant in Dutch), Zibenbergen - זיבּנבּערגען (Yiddish), Zivenbork (Walloon)