Stachelberg, Military fortress near Žacléř, Czech Republic

Stachelberg is an underground military fortification near Žacléř, in the north of the Czech Republic, dug into a forested hill. It consists of a network of tunnels and chambers at different levels, designed to shelter soldiers, weapons, and communications equipment.

The fortification was built in the late 1930s as part of a long defensive line meant to protect the Czechoslovak border. Before it could be completed, it was overtaken by the 1938 Munich Agreement and the subsequent occupation of the Sudetenland.

The Czech name Ježová hora was officially adopted in January 1938, yet the German name Stachelberg and the local name Babí remain in use; the museum itself is named Stachelberg. The site is run by the Stachelberg Civic Association, volunteers who took over from the Trutnov firm Fortis in 2005 and fund the museum from entrance fees and donations.

Access to the site is through guided tours, as the underground passages are difficult to navigate without a guide. It is worth bringing warm clothing, since the temperature underground stays low throughout the year.

The fortress was planned with twelve bunkers, but only the infantry blockhouse T-S 73 was ever completed. In the 1980s it served as a chemical store for aredin, which was removed in 1990. The underground was flooded until 2000.