The courses are so many, so you have to do a list in before and check out your interests, then after the first or second week (but not later!) decide what you are going to do that term. My interaction with other international students was so bad because history is a subject mostly German students study. I saw only five (from a few thousand overall students) international students at the Institute of History. If you want to get in touch with students at all, do not go at too many lectures. You get to know students if you go to seminars and have to cooperate with them.
Guide yourself not just by the title, try to get some deep info about the course and if it belongs to the first years (basic theory contents) or to the upper years (more practical interactive courses). Try to participate, and always talk with the teachers to "negociate" about works, exams and how they can help you (main problem is mostly the language!).
My courses were predetermined and lasted only 6 weeks. They included an economic history of Germany, Unification Issues, Life in Cold War East Berlin and introductory German language classes. It is best to try and immerse yourself in the host language as quickly as possible. I found it hard to talk with locals becuase they wanted to speak in English as soon as they heard my American accent. All courses on German history during the Cold War are fascinating. Berlin provides the best possible "city as classroom" opportunity I can think of. Locals can still tell you first hand stories of life during and after the Cold War.
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