Тhe fortress was built by the Ottomans in the beginning of the 18^th century and ranks among the best preserved in the Balkans. The walls are 2 metres long, 8 metres high and 4 metres thick. The fortress was built on the foundations of the ancient city of Naissus. In the past it was surrounded by a ditch from all sides, but today there´s such only in the northern side of the fortress. Within the Nis Fortress, tourists can explore the Arsenal, the renovated mosque of 1521, which houses an art gallery, the Historical Archive´s building, the Lapidarium, preserving many ancient monuments and inscriptions, the Turkish hammam and other attractions. Nowadays, the Nis Fortress is set up as a city park - a pleasant place for walk during the summer.