Kastel Fortress

Kastel Fortress is the stone heart of Banja Luka and the city's oldest monument, set in the centre on the left bank of the Vrbas, near where the Crkvena flows in. Life has gone on here for millennia – traces of a Neolithic settlement and the Roman fort Castra, from which the fortress likely takes its name, have been found. Kastel gained its recognisable form, with mighty stone walls, bastions and towers, in the Ottoman period, especially under Ferhad-paša Sokolović, and was later extended in the 18th century.

Once a stronghold guarding the Vrbas valley, today it is a calm oasis amid the city bustle: within its walls are a summer stage, a gallery, a children's playground and a riverside restaurant. In summer Kastel comes alive with concerts and festivals such as Demofest and Freshwave. It was last thoroughly restored in 2016 and remains the city's main symbol.