Ruud Streefkerk

From the Grianan of Aileach, a large Ringfort right on the border of Northern Ireland and the Republic of Ireland, you have a wide view of Donegal and the Inishowen peninsula. The Greenan Mountain is 244 m high and consists mainly of sandstone and slate, covered with marsh and heather. The Ringfort on the  top dates from the 6th century, but probably the hill was already used long before that time, because just outside of it, the remains of a Neolithic Tumulus and a well were discovered. The fort consists of 3 terrace edges with a thickness of 4.5 m. Originally there were buildings inside: they were the seat of the Celtic kingdom of Aileach, which in the12th century lost much of its power and territory to invading Normans.