To get a sense of what the wall and the dead man's land in between looks like, look no further than the Memorial of the Berlin Wall at Bernauer Strasse.

Called the Dokumentationszentrum Berliner Mauer, this strip of wall gives a unique perspective of the wall, from above.

The visitor's center (free admission) has several movies and documents in German, but knowing German is not necessary.  The movies invoke enough imagery that there is no need for translation

There is also the Chapel of Reconciliation and a Documentation Center. At the center you can read everything about the history of the wall. 

A tower (accessible by stairs or elevator) enables you to view this section of wall and gives a sense of how massive it really was.

The center is not close to all the other attractions of Berlin, which makes it less touristy. This memorial does an excellent job showing how the wall system worked.

A few minutes walk away is the Nordbahnhof station.  In the "lobby" down one flight of stairs, is a photographic display of what happened to the U and S bahn stations when the Wall divided Berlin.  This is of museum quality, with extensive text in English and German.