I had a wonderful month-long stay at Christopher's apartment. You cannot ask for a better location, with grocery shops, the Museum Island, Alexanderplatz, Hackesher Markt, all within 15 mins walking distance. The apartment is well-equipped and has a breathtaking view. The only issue I had was connecting the wifi, which should have already been solved now. Christopher has responded swiftly to my questions during the stay. All-in-all highly recommend this place.