The most ancient architectural and archaeological monument of Bukhara is the Ark ancient fortress. It is located on a bulk hill about 20 meters high. Its area is 4.2 hectares. According to the plan, the Ark is a closed polygon. The Ark is surrounded by a fortress wallon all sides, the construction time of which dates back to the last two or three centuries. It was rebuilt and repaired many times. This wall is the most vulnerable on the northern slope; one can count up todozens of supports here.