Kayan fortress was one of the important defensive points of medieval Armenia. Here, during the attack of the enemy, the monks of the Ahpat monastery and the inhabitants of nearby villages found protection.
Kayan fortress is located on the North-Eastern side of the village of Ahpat. The question of when exactly and by whom the fortress was built has not been fully clarified, but in all probability it was rebuilt in 1233 by the Abbot of the monastery of Haghpat, Bishop Hovhannes.
The fortress stands on a triangular promontory, which is formed by sheer cliffs descending into the gorge. The natural protection of the area was enhanced by about fifteen semi-cylindrical towers with strong walls. The main entrance to the fortress was on the South side, where the Cape connects to the village through a gorge. In the gorge, the road passes through a bridge of the XIII century over the river Sherek.
The length of the fortress from the South to the North is about 120 m, and the width does not exceed 20 m.the Kayan fortress consists of two parts: the main part is the southern Part, which is at a higher height and is separated from the Northern part by a wall, in which a vaulted hall was added. The Northern part of the fortress, which adjoins directly to the edge of the Debed gorge, is about one and a half times smaller than the southern part. The Northern part had a separate entrance from the Western part. Inside, a large number of ruins of residential buildings, swimming pools and water supply systems have been preserved.
In the southern part, on the top of the cliff on the Eastern side, on a place that is clearly visible from all sides, stands the Surb Astvatsatsin Church of Dsevanq.