Munich's historic Old Town is also the downtown area. This is where you will find many historic buildings as well as Marienplatz, (the historic central square), and the Residenz. In the past, further expansion was hindered by the Englischer Garten to the northeast and the Isar River to the east. Within the boundaries of the old town gates – Karlstor, Isartor, Odeonsplatz, and Sendlinger Tor – lie the principal shopping districts. Here you will find the pedestrian zone, Theatinerstraße, and Maximilianstraße. However, Marienplatz remains the true heart of Munich for visitors and locals alike.