Topped by a single spire, the red-sandstone Alte Nikolaikirche (Old St Nicholas Church; alte-nikolaikirche.de) – begun in the 13th century – is situated on the south side of the Römerberg and was one of the few Altstadt structures to survive WWII almost intact. In the tranquil interior, under late-Gothic vaulting, are stone carvings and 14th- and 15th-century gravestones.
The church is known for its intricate system of bells, which are most likely the ones you hear most often marking the time. Of the 51 bells, four are used for peals and 47 are used for carillons – two different types of ringing styles. Hearing the bells chiming from the square after a day of sightseeing is a signature Frankfurt experience to be remembered.