Tvrđava Kanli Kula, which translates as "the bloody tower" is a fortress in the northern part of the Old Town in Herceg Novi. The fortress was built in the times of the Ottoman empire. It was first mentioned in records dating back to the XVII c. The fortress was used as a fortification element and a prison.

These days, the fortress is open for tourists (the entrance fee is EUR 2). If you make it to the top, you can enjoy a wonderful panorama of the town and the seaside. The fortress has one of the largest amphitheaters in the Adriatic. In the summer, it hosts various dramatic performances and concerts.