Heiligenkreuz Abbey built
1101 CE.
Shown on the map at 48.055°, 16.131°.
Heiligenkreuz Abbey (German: Stift Heiligenkreuz, lit. 'Abbey of the Holy Cross') is a Cistercian monastery in the village of Heiligenkreuz in the southern part of the Vienna woods, c. 13 km north-west of Baden in Lower Austria. It is the oldest continuously occupied Cistercian monastery in the world.
Text from the Wikipedia article Heiligenkreuz Abbey, licensed CC BY-SA 4.0.