Kluže, Historic fortress in Bovec, Slovenia.

Kluže is a fortress built into the rock at the entrance of the Koritnica gorge in Slovenia, with thick stone walls rising directly from the cliff face. The structure includes gun positions, narrow corridors, and parapets designed to block the passage through the gorge below.

A Venetian fortress stood here from 1471 until the Venetians left in 1478; the Habsburgs built a new fort in 1509. In 1797 Napoleon's artillery, firing from the slope where Fort Hermann now stands, hit and burned the fort. The Austrians repaired it after their defeat at Ulm, but the ruins stood empty until construction of the present fort began on 28 March 1881 and ended on 14 November 1882.

The fortress is used today as a venue for local events, open-air performances, and small exhibitions held within its stone walls. The setting inside the gorge gives these gatherings a character that no ordinary hall could offer.

The fortress stands beside the road just before the bridge over the Koritnica, at the narrowest point of the valley. The two forts are connected by a trail and a tunnel, so allow time to walk between them. The ground is uneven, and sturdy footwear helps.

Fort Hermann, the upper fort on the Rombon slope, was built because the lower Kluže fort became obsolete as artillery developed; it was meant to cover the lower fort in case of attack. Italian artillery heavily damaged it in 1915, leaving it unusable. A trail and a tunnel link the two works.