If you want to see the top sights of the city, you won't get passed the cathedral. During the Middle Ages the Frankfurt Kaiserdom (Imperial Cathedral) was where German kings were elected, and later the crowning church of Holy Roman emperors. It evolved from the Salvatorkirche that was endowed by Ludwig II. in 852, and rebuilt in 1953 after severe damage had occurred during World War II. Today it harbours valuable altars and tombs of the late Gothic era. Of course, most of the time it's quite calm and contemplative here, however, different events, changing exhibitions and church services on Sundays bring life into the old walls.

If you don't want to stay inside for too long, a visit will still be worth your time. You can climb the cathedral's tower and enjoy a beautiful view of the city. And the final surprise: Admission is free!