Tripadvisor does not have a review category for the Brandenberg Tor U-bahn station. Yet it is as interesting as the gate. The Brandenberg Tor station has existed since before WWII. It was vacant during the Cold War, so it is perfectly preserved.
I love going into the Brandenberg Tor station and seeing the well preserved 1930s station. (If you ride U-55 Hauptbahnhof to Brandenberg Tor, walk toward the Brandenberg Tor exit and watch for the tiled portion of the station. That is the old part of the station.) The tiled portion of the station sat idle prior to unification.