Grianan Of Aileach – This prehistoric stone fort is located at the top of the sacred Greenan hill (250 meters above sea level) near the village of Burt in County Donegal, about 17 kilometers west of Derry (road N13 towards on Letterkenny).
It was not only a place of religious worship, but also a well-chosen strategic place, hence it was possible to see the enemies in motion from really long distances, which was a military advantage.
The current structure from the first century AD was restored in 1874-79 by the antiquarian Dr. Walter Bernard, although the beginnings of this stone fortress are noted for the Bronze Age around 1700 BC and built by Tuatha de Dannan, who invaded Ireland and ordered the construction of forts in strategic places, the aim of which was to defend against the Celts.
The fort then changed owners from clan to clan, and from the 5th – 12th century it served as the royal seat of the Ui Neill clan, who were the rulers of much of Ulster.
In 1101, the structure was badly damaged by the O’Brien clan – the Munster rulers – legend says that this Murtagh O’Brien ordered his soldiers to take all the stones from the great fort so that nothing would be left of him – but despite their efforts, fortunately it failed and most of the stones remained on the hill.
This place was a very important construction from its time, which is proved by the fact that the fort found itself in only five Irish places marked in a large world map from the second century written by Ptolemy of Alexandria (astronomer, mathematician and geographer of Greek origin).
The diameter of this circle is 23 meters and the walls of this stone palace have a thickness of almost 4 meters and a height of 5 meters and it should be noted that most of it is built without mortar.
Grianan Aileach is amazingly impressive due to its simplicity and construction, and from the very top it shows a truly breathtaking view of the whole area, so you can not miss it while visiting Northern Ireland or County Donegal.