My favorite lake to visit during the warmest months. It's located in the southwestern part of Berlin and it's reacheable by public transportation, just around 40min from the city center.
It is the highest place in Berlin and is made of wartrash. Translated Teufelsberg means "Devils Mountain". The whole area always reminds on how beautiful Berlin is: On one side you see the big city and when you turn around pitch black forrest.
It's a small bookshop to be stuck forever. Here you can find the most beautiful collection of art/photography/architecture/fashion/food books and magazines, not to count it's just a walk distance to diverse galleries around the neighborhood.
Wim Wenders shot Wings of Desire here. It's a quiet place to work and definitely a gorgeous place to visit. Combine it with a visit to the Philharmonic, just across the street. Affiliation is 30 euros per year and you have lots of desks all over the library to choose from.