Roman Limes at Aalen (Kastell Aalen)

The Roman fort at Aalen, in Baden-Württemberg, was built around 150 CE as the base of the Ala II Flavia milliaria, a 1,000-strong cavalry unit, making it the largest Roman cavalry fort north of the Alps. The fort formed part of the Upper German-Raetian Limes, the fortified frontier line separating the Roman Empire from unconquered Germanic territory, and is inscribed as a UNESCO World Heritage Site along with the rest of the Limes system. Excavated foundations mark the outline of the fort's barracks, headquarters building, and defensive ditches, while the adjoining Limesmuseum Aalen displays recovered artefacts including cavalry equipment, horse harness fittings, weapons, and everyday objects from the garrison and its surrounding civilian settlement. The museum's exhibits are arranged thematically, covering the daily life of Roman soldiers, the cavalry unit's equipment and tactics, and the broader function of the Limes as a monitored rather than fully sealed border. A full-scale reconstruction of a Limes watchtower stands near the museum, giving a physical sense of the frontier's surveillance infrastructure alongside the fort's archaeological remains. The Romans abandoned the frontier around 260 CE under pressure from Alemannic incursions, after which the fort fell out of use. Conservation of the excavated remains and museum collection is maintained by regional heritage authorities as part of the wider Limes UNESCO designation.