The original Nikšić was built within sturdy walls on a rocky hill to the west of the current town. This was the site of a 4th-century Roman military base that was taken over by the Goths and fortified. Today, the partially restored fortress hosts an annual music festival.
From Ulica Njegoševa, take Ulica Narodnih Heroja to the end, where you’ll see the fortress ahead of you. It's near the train station.