The Pannonian Limes is a part that is mostly found in Hungary from the Roman front line known as the Danubian Limes, a line of castles and fortifications along the Danube River. The fortification line included guard towers, legionnaires’ camps (castra) and forts (castella).
The plaques are located in the March 15 square in Budapest where one of the camps stood, describing the relative location of the camps along the Danube which is also drawn on the sidewalk.
The current plaque shows A Március 15. tér, which is the square where the plates of the fortress line are located, and also formerly a Roman military camp. The camp called Contra Aquincum was built in the early second century AD, and rebuilt in the late third century AD and survived until the fifth century AD.
Notice the two lines representing the Danube River on the left side of the plaque.
In the next photo taken on the same day, part of the line of fortresses was seen, with the route of the Danube River between the various plates Click for a larger image