It is a 28 meter wall which is the remnants of Tabriz city citadel and city wall. Ark was firstly made as a very big mosque in thirteenth century, however the devastating earthquake and other natural disasters ruined much of it except the main wall of the mihrab which is preserved till today. In later years this wall used as part of the city wall and the main part of fortress of Tabriz till end of Qdjar dynasty. During the wars of Safavid-Ottoman, and Perso-Russian wars this fortress was always one of the major Strong holds of Iranian troops. In early 20th century the constitutional revolutionist used the ark citadel as their military base in Tabriz. At the collapse of Autonomous Government of Azerbaijan Ark was the latest resistance of their troops against Iranian army. In recent years the surrounding area of Ark is used to build another big mosque for Friday prayers.