This unique military monument from the years 1937–1938 was part of extensive border fortifications built to protect Czechoslovakia against Nazi Germany.
It was an artillery fort, which was meant to consist of several sub-buildings. In September 1938, construction was completed on the surface only of the Zelený artillery cabin and Můstek and Jeřáb infantry cabins. After the Munich Agreement further work was stopped. Visitors have been exploring the unfinished fortress since 1969. Before descending into the underground, they will see 38 calibre 100 mm mock-howitzers on the top floor, which resemble the main armaments of the cabin. In another part of the exposition you can see Europe's only collection of miniatures of soldiers of the Czechoslovak Army before World War II. A photo panel documents the events leading up to the Munich Agreement. The area includes a nature trail. The fortress is operated by the Regional Museum in Náchod.