Zahak Castle, which in the local dialect is called Nouri Ghala, is located in 20 km to the southeast of Hashtrud County within the central part of Ali Abad village and five kilometers to the south of Arablu village in East Azerbaijan. This castle was first discovered and examined by a group of German archaeologists in 1971. From historical discoveries and researches it is concluded that the castle of Zahak belongs to the Parthian and Sassanid dynasties.
Zahak Castle in historical writings has been documented by other names such as Castle of Azhdahak, Qiz Qal’eh Si, Dash Qal’eh Si, Baruas, Rouyi Dej, and Qal’eh Guyi. In addition to the signs indicating the military function of the castle it is believed that like other castles of Dokhtar in Firouzabad and Arg-e Bam, it is a shrine and place of worship related to Anahita and has been built in connection with the worship of sun.
This castle was also habitable during the Islamic era and twelfth and thirteenth centuries and matched the ideals of Isma’ilism who were fond inhabiting ancient Iranian castles.
The entirety of the land of Zahak Castle is about 10 km in length and 2 km in width. This castle is surrounded from three sides by cliffs and its walls have carvings. Even though today the only remaining part of the entrance of the castle is a Chahartaq, but still you can speak of various parts of the Zahak Castle and locations like the decision making hall, half-cylinder towers of the gateway, rooms with no roof, rooms dug into mountain, stone storages, water storage rooms with shelves, mills, colored stones, cleansing rooms, as well as clay plumbing pipes that would fix into one another with a half a meter width that were providing the water of the castle.
Chartaq of the Zahak Castle is made from brick and mortar and has remained from the Parthian era. The bricks of this square room are 32 by 32 and have heights of 10 cm. Even though this room of Zahak Castle has lost its ceiling and one of its historical columns, these parts have been renovated and rebuilt.
In the Zahak Castle, a painting has been discovered that spreads in an area of 121 meters and depicts a crow that is pointing its claws into the back of a cow. The crow is a symbol of Mithraism and at times in this religion, it is a being that through its killing herbs and vegetation are created in the world.
In addition to the painting of the crow and the cow, there are other paintings that have been discovered through archaeological excavations such as the Parthian soldier, the heads of a few roaring lions, the goddess and the man within the lotus with sun rays.
In the last few years, numerous parts have been added or provided to ease the accessibility to this historical building for the viewers and the visitors such as stairway for accessibility to the gateway, the stone stairs around the building, security fences around the cliff on all three sides, the metallic bridge on the river as well as the museum of ancient excavations and historical findings.