Altstadt Spandau is the historic centre (the old city) of the borough (Bezirk) of Spandau in the western suburbs of Berlin. It is one of the four zones of the locality (Ortsteil) of Spandau.
The Altstadt is situated on the west bank of the River Havel by its confluence with the River Spree. It was protected from attack by the Spandau Citadel, on an island between the two rivers.
The Spandau Citadel (German: Zitadelle Spandau) is a fortress, one of the best-preserved Renaissance military structures of Europe. Built from 1559–94 atop a medieval fort on an island created by the meeting of the Havel and the Spree. In recent years it has been used as a museum and has become a popular tourist spot.
(sources: en.wikipedia.org/wiki/Altstadt_Spandau and en.wikipedia.org/wiki/Spandau_Citadel)