The Secret of Unška Koliševka

Discover one of Slovenia’s largest karst collapse dolines and uncover its hidden past. Around 125 metres deep, Unška Koliševka conceals a remarkable network of underground military tunnels, bunkers, and fortifications nearly a century old. These structures form part of the largest interconnected fortress system on the front line of the Alpine Wall, built by Italy between the two World Wars as a defensive line stretching from France, across the Alps, to what is now Slovenia. Accompanied by an expert guide, you’ll explore this fascinating labyrinth of underground passages and discover a little-known chapter of history that shaped the region. Tours last between 2 and 2.5 hours and are conducted in small groups, making the experience ideal for private groups as well as curious individual explorers.