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 Crumerum, the Roman name of the fort in Nyergesújfalu, Hungary. The fortress was built during the reign of the emperor Trajan (end of the first century - beginning of the second century AD) and was used until the end of the fourth century AD.
Notice the two lines representing the Danube River in the upper side of the plate.
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