This place is like being in the Canary Islands, where my hometown is. The wonderful botanical garden has around 22.000 different plant species. I can find here all the tropical species from the island where i grew up: birds of Paradise, palms or dragon trees.
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.
One of the most beautiful pieces of Berlin actually is a piece of another city (Al-Hillah, Iraq). Normally Berliners are laid back and like to hang around, drink beer and chat till sunrise. Sometimes they do get excited though, and then they start taking old war-battered stones and piecing them together to (re)form walls. The results are great as can be seen all over Berlin, but the Ishtar gate in the Pergamon museum is where they’ve really outdone themselves.
Kw is a great art institute situated at the backyard of a very eastern part of town, place for many other small galleries. Auguststrasse is worth the walk and Kw is worth the stop.