The image and the purpose of Fort Kluže has varied in the course of history.
It blocked an important strategic passage at the narrowest section of the Koritnica. The Venetians were the first to construct a wooden stronghold on this site in the second half of the 15th century. It served as a defence against the Turkish inroads. The first fortification made of stones was erected at the beginning of the 16th century, subsequently being renovated several times.
In the period of Napoleon Bonaparte, more precisely in 1797 when the French wars began, it was set on fire and pulled down. A new fortification, whose practically unchanged image has been preserved until the present day, was built under Austria-Hungary in the years 1881–1882. It was named Flitscher Klause (Kluže of Bovec). It provided control over the passage from the Bovec basin, across the Predel/Predil Pass to the inland of the Austro-Hungarian monarchy. When the Isonzo Front was opened, the frontline stabilized in its immediate vicinity. Situated below the steep faces of Mt. Rombon, the Fort was safe from direct Italian shelling. Placed in it were the commands and rear troops, and a dressing station. Many safety and supply facilities were added to it, such as a small power plant, water-pumping station, observation posts with searchlights and the like. In the years before the Second World War the Fort was ravaged. Now, a museum is arranged in Fort Kluže, with a permanent and several temporary exhibitions.