Kastel Fortress

Kastel Fortress is a stone fortress in Banja Luka built with thick defensive walls, watchtowers, and artillery positions positioned along the Vrbas River. The complex includes an underground passage system, a restaurant, and various defensive structures that visitors can walk through.

The site was originally a Roman military camp called Castra established in the 4th century BC. Over two millennia, the location was repeatedly rebuilt and expanded until it developed into the fortress that stands today.

The fortress hosts summer concerts and performances on an open-air stage, while the Kamena Kuća cultural center operates inside its walls. Families also use the children's playground, giving the site an active, community-oriented feel.

The grounds are easy to explore on foot and the underground passages are accessible during regular hours. There is parking available on-site, and the restaurant inside offers a good place to rest and refuel.

Beneath the fortress walls lie archaeological layers stretching back to the Stone Age, including an ancient burial ground with non-standard burial practices. This layered history shows how many different peoples occupied the same location across thousands of years.