The Römer is a medieval building in the Altstadt of Frankfurt am Main, Germany, and one of the city’s most important landmarks. The Römer is located opposite the Old St. Nicholas church and has been the city hall of Frankfurt for over 600 years. The Römer merchant family sold it together with a second building, the Goldener Schwan , to the city council on March 11, 1405 and it was converted for use as the city hall. The Haus Römer is actually the middle building of a set of three located in the Römerberg plaza. The Römer is not a museum as it is occasionally used by the city for various purposes, for example as a Standesamt or civil registration office; the wedding rooms are located in the first and second floor of the Haus Löwenstein. The former old town quarter between the Römer and St. Bartholomew’s Cathedral will be redeveloped as the Dom-Römer Quarter until 2016, including several reconstructions of historical buildings that were destroyed during World War II.

More details: https://en.wikipedia.org/wiki/Römer