I see that Blogger had some down time, and my posts from Wednesday, which I thought I published, and Thursday have been lost. I'll take that as a message that my posts have been too long and detailed, and I'll summarize things briefly.
On Wednesday I went to Potsdam: much to see in the rococo palaces of Frederick the Great; in the late afternoon there was a thunderstorm as I got to central Potsdam and ate at a creperie. Back in Berlin, I ate at the Vietnamese restaurant Monsieur Vuong.
On Thursday I bought the €40 Annual Museum Pass, my first use of a credit card in Germany, and it may be my only one; I know not to count on restaurants taking them, and all my meals have been under €20. The museums I saw were the Bode (two blocks from me on Museum Island); in the West the Neue Nationalgalerie and the Gemaeldegalerie, and the Photography (Helmut Newton) Museum. In the last area, down the main Ku'damm shopping street, I finally tried the local Currywurst specialty at a place where people eat at stand-up tables; then once again there was a downpour. Also during the day I saw the Sony Center and Potsdamer Platz, a square formerly divided by the wall, now showing massive commercial building.
Today I had a full breakfast at Keyser Soze, then it was my day to see far-flung museums. With a day pass, I took the S-Bahn to Charlottenburg and changed to a bus to see the Berggruen Collection(across from Charlottenburg Palace, almost all a postwar reconstruction and which I didn't take time to see). The Berggruen is a nice 3-story building devoted to Picasso and His Time, including nice works by Matisse, Braque, and Klee.
Now, with a bus and a couple of U-Bahn lines, to Dahlem, a museum complex on the southern outskirts with impressive ethnological collections from outside of Europe (a European collection is temporarily closed). There was an interesting setup of African collections in dark rooms with lighting on the art. Even though I had a full breakfast, I broke for lunch with gnocchi from their cafeteria. The museum had very few visitors.
Afterwards, I had time, as I wished, to return to Checkpoint Charlie and look at the outdoor display on the history of the Wall and crossing point. I took the U-Bahn the few stops to my area and had a pizza. Tomorrow, getting into the major Island Museums.