We had a wonderful staying at Fulvia's apartment. It's really close to the center- it takes a 10mins walk to the next subway station and then just 2 stops to Potsdamer platz- what is really close to the brandenburger tor. Day tickets are 7 euros per day so we took the public transport everywhere. The Wi-Fi is working perfectly and the apartment is really cozy. The only thing we were expecting more was the kitchen. You can't really cook. It's more a pasta/ breakfast kitchen. But it doesn't really matter since there are lot of restaurants and fast food stores around the corner. If you want to open the window: there is a window you can easily open- the second window can be opened by a key-ish typ of thing which you can find between the windows. We can definitely recommend this apartment with a very good value. Thanks a lot, fulvia!