Petersberg Citadel
Start high. The ramps and bastions of the Petersberg pull you up above the rooftops, and the first thing you do at the top is turn around: the whole old town spreads out, cathedral hill on your left, red roofs everywhere else. This is the largest preserved baroque town fortress in central Europe, built from 1665 on the orders of the Mainz elector as a stronghold against the city itself. The grounds are free and open daily 10:00 to 18:00, so just walk the walls and orient yourself. The paid extra is the guided tour of the underground passages, the horchgänge listening galleries inside the ramparts, at €9 adults, €4 reduced. Worth it if you like military engineering, skippable on a first quick loop. Give the viewpoint ten minutes, find the cathedral towers, then head downhill toward the monastery.
Learn more about Petersberg Citadel →10 min walk to next stop










