Alte Burg

Alte Burg - Credit: Wikimedia Commons

The Alte Burg (also Alte Burg im Quecken or Alte Burg "am Quecken") in Bad Münstereifel, Germany, is a circular rampart that is the remains of a fortification from the Carolingian period. The refuge castle acted as a place of retreat for the local population and as protection for the daughter monastery of Prüm Abbey. The defences dating to the 9th century have been designated as a protected monument. The castle site lies within the county of Euskirchen in the state of North Rhine-Westphalia. Read more on Wikipedia

type: military installation
date from: 9th century

Source: en.wikipedia.org