Along the road leading to the Peak of the Three Holy Kings lies the entrance to an artificially formed horizontal tunnel that runs throughout the entire peak. The Rupnik military and defence line carried out excavations in the area in the 1930s. During these excavations, the Cave of the Three Holy Kings was discovered. The cave is intertwined with small tunnels that are more than a kilometre long and 70 metres deep. Information and visits are available by prior arrangement from: .