View over the River Spree to Nikolaiviertel and Alexanderplatz. The Nikolaiviertel is the reconstructed historical heart of the German capital Berlin. The Nikolaikirche (Saint Nicholas Church) gives its name to the neighbourhood five minutes away from Alexanderplatz. The Alexanderplatz is a large public square and transport hub in the central Mitte district of Berlin, near the Fernsehturm the Rotes Rathaus, the town hall of Berlin.