Appleby Castle built
1120 CE.
Shown on the map at 54.574°, -2.489°.
Appleby Castle is in the town of Appleby-in-Westmorland overlooking the River Eden (grid reference NY685200). It consists of a 12th-century castle keep which is known as Caesar's Tower, and a mansion house. These, together with their associated buildings, are set in a courtyard surrounded by curtain walls. Caesar's Tower and the mansion house are each recorded in the National Heritage List for England as a designated Grade I listed building. The uninhabited parts of the castle are a scheduled ancient monument.
Text from the Wikipedia article Appleby Castle, licensed CC BY-SA 4.0.