A very nice and convenient flat literally 30 seconds from the Nordbanhof subway station, from which you can get to anywhere in Berlin. The flat itself is spacious, well lit, and extremely modern, but it has one drawback in the summer: being on the ground floor, you may want to close the steel shutters on the windows at night, but this leaves the apartment without any air circulation, so it can get pretty warm. An alternative we didn't try is to keep the shutters open and pull the top of the windows partly open; but I'm not sure how much air circulation this would create.