To call abroad from Germany, dial 00 followed by the international country code and the local number. To call Germany from abroad, dial the international access code followed by the German country code (49), and the city code or mobile number, dropping the initial zero. Calls to mobiles (Handys in German) require the initial zero.
The phone codes for Germany's largest cities are: Berlin 030, Bremen 0421, Düsseldorf 0211, Dortmund 0231, Essen 0201, Frankfurt 069, Hamburg 040, Köln/Cologne 0221, München/Munich 089, Stuttgart 0711.