A quick recommendation for an exceptional guide in Berlin -- Robert Sommer. A short biography will give insight into why he deserves consideration for a tour. Robert was the 15-year-old son of a high-ranking DDR (East Germany) bureaucrat and was part of the punk rock scene when the Berlin Wall fell in 1989. As a part of that scene, he fought with neonazis. He has interesting stories about what he and his family did when the wall fell, and its interesting to ask which capitalist item he bought first and which he held out against the longest. He was a squatter post-unification. He ended up getting a PhD in history with a thesis related to prostitution in WWII prison camps. He married a woman who was in Germany’s Parliament for an extended period of time. He's a fascinating guy.
He has standard Berlin tours on his website. But he can offer so much more. I did a tour of Seelow Heights (site of a large WWII battle east of Berlin) and "Fortress Küstrin" which now exists as a Pompeii-like town. I've explored abandoned Soviet military bases and stood in bunkers used by the Soviets to store nuclear warheads during the Cold War. Most recently, I gave Robert some concepts for a tour, and he crafted a tour he called "The DDR: From the Dream of Communism to Neonazi Violence." Robert discussed the DDR’s use of art, architecture and open space as means to promote community in the area around Alexanderplatz and along Karl Marx Allee. We viewed a couple of the few remaining squatters' buildings in the old East Berlin. We went to Marzhan to see a large residential complex built by East Germany and to hear Robert's stories of growing up there, including fights/wars between neonazis and punk rockers. We finished up the day with a visit to Alt-Marzahn village, an old village in the midst of the larger surrounding development. We had a late lunch at the village's butcher shop, which also had some prepared foods. We enjoyed some quite good Bulette; our Apfelshorle were so good we both had a second one. An astoundingly good tour with an astoundingly great guide