The towering brick mass at the eastern end of Am Sande is St. John the Baptist, the city's main parish church and one of the most striking examples of North German Backsteingotik (brick Gothic) anywhere. The choir was begun around 1300; the great west tower, finished in 1406, was for some time the tallest in Germany. It famously leans — a problem since at least the 16th century — and surveys show the lean is still slowly increasing.
Inside, the long nave is calm and spare, with a notable late-15th-century carved high altar attributed to the workshop of Hinrik Funhof. The young Johann Sebastian Bach attended the attached Michaelisschule from 1700 to 1702 and would have heard the church's then-new Niehoff organ; a much-altered version is still in use today. Free entry, open daily.