Mainz Citadel

Mainz, Germany, Germany

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Mainz Citadel is a large 17th‑century baroque fortress complex built between 1655 and 1669 on the Jakobsberg hill above the old town of Mainz, Germany, originally designed as part of the city’s defenses within the greater Fortress Mainz system.

It has a regular, almost rectangular layout with four bastions named Alarm, Tacitus, Drusus, and Germanicus at the corners, making it one of the most important early‑modern fortress structures in Rhineland‑Palatinate.

Over time the citadel served as a military stronghold, later becoming home to barracks and facilities connected with the federal fortress of Mainz in the 19th century, and it also includes air‑raid shelters and underground passages from more recent history.

Today it is no longer a military base but houses municipal offices, the City History Museum, and other public uses, while remaining a tourist attraction with wide views over the city and the Rhine.