There is a beautiful map from the time of Frederick the Great that includes both Berlin and Potsdam.  It manages to articulate in a single drawing both the geography of the region and the structure of the cities and towns.  It allows us to see particularly well relationships at different scales.

You can think of this map as a drawing of points, lines and planes.  Urban settlements appear as red dots, a couple of them very large--Berlin and Potsdam--and the majority much smaller, located at the intersection of secondary roads or at the edge of waterways.  There are two major lines, the  meandering Spree and Havel rivers, and then a whole network of more or less straight roads connecting urban settlements.  Finally, there are the large swats of green indicating forests, mostly along the edges of the rivers.

It is particularly interesting to see the different way in which the two major cities relate to their geography.  Even as early in the mid 1700s, Berlin appears as if it would have swallowed the river within its fabric.  And if you look Charlottenburg to the west, it's easy to fast forward to a time when the city fabric will surround the Tiergarten.  By contrast, Potsdam is already defined by the articulation of city, water and open land--forest and parks--that has characterized the city all the way to the present.

If you pay attention to the names of the smaller points in the map, you'll recognize neighborhoods of today's Berlin, like Zhelendorf, Steglitz and Britz to the south, or Spandau, Tegel and Marzhan to the north, just to name a few.