The best cheeseburger in Berlin costs less than 5. Burgermeister is mandatory in town when you're craving for a basic and delicious to the bits chesseburger.
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.
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.