The Danubian Limes, or Danube Limes, refers to the Roman military frontier or limes which lies along the River Danube in the present-day German state of Bavaria, in Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria and Romania.
The Salz Tower (Salzturm) in Tulln, Lower Austria, the former western horseshoe tower (Hufeisenturm) at Comagena
Remains of the castrum in the Belgrade Fortress
Limes is a term used primarily for the Germanic border defence or delimiting system of Ancient Rome marking the borders of the Roman Empire. The term has been extended in modern times to refer to the frontier defences in other parts of the empire, such as in the east and in Africa.
Limes Africanus under Septimius Severus (the frontier of Roman Africa (dark tan) in the late 2nd century AD: Septimius Severus expanded the Limes Tripolitanus dramatically (medium tan), even briefly holding a military presence (light tan) in the Garamantian capital Garama in 203)
Reconstructed east gate of the fort at Welzheim, Germany
Reconstructed wooden tower nearby Rainau, Germany