The Čolina Kapa Astronomical Observatory sits on a ridge above the city at around 970 metres altitude, occupying the ruins of an Ottoman fortress that was itself built on a site with panoramic views over the valley. The observatory is functional — it hosts public stargazing evenings and school groups — but its setting is the main draw for visitors: the approach through the forested ridge above the city and the views from the Ottoman walls are extraordinary.
It is a genuine hike to reach the observatory from the city, or a drive on forest roads that may require a high-clearance vehicle in winter. The combination of astronomical site, ruined fortress, and wartime history makes it more layered than it initially appears. Check the observatory's programme for public evenings before making the climb.