The remains of a Roman fortress built in AD 120, the Römerkastell-Saalburg could accommodate a cohort (500 men) and was part of the fortifications along the Limes Wall, which ran from the Danube to the Rhine and was meant to protect the Roman Empire from barbarian invasion. The fort was restored more than a century ago. The site, which includes a museum of Roman artifacts, is 6½ km (4 mi) north of Bad Homburg on Route 456 in the direction of Usingen. It's accessible
by direct bus service.