Bunker B-S10
Bunker B-S10: Reconstruction of the infantry bunker B-S 10 "Three Borders" from 1934-35.
After the establishment of Czechoslovakia in 1918, the border with Austria and Hungary was considered a potential future battlefield. Bunker B-S10 “Three Borders” is part of a fortified bridgehead composed of several bunkers, mainly on the Petržalka side of Bratislava.
The design, construction solutions, and details resulted from direct cooperation with France, which shared its experience with the Czechoslovak army during the construction of the Maginot Line.
The construction of the bunker took place between 1934 and 1935. The partially buried massive structure has a reinforced concrete shell 1.5 meters thick. Several structural modifications were already carried out during the interwar period. The bunker was designed to accommodate 10 soldiers, primarily operating two heavy machine guns with a capacity of 100,000 rounds. The defense system also included a mechanism for throwing grenades into areas outside the defenders' line of sight. A light machine gun with a rotating turret was never implemented. The turret opening was later concreted over, leaving space for a periscope. The bunker was later equipped with a pedal-powered ventilation system, based on a bicycle mechanism, with a capacity of 800 m³/h air exchange. The bunker never saw actual combat. It remained unnoticed until 2017. This isolated, inconspicuous structure in the middle of a field, close to a highway, was searching for a new purpose.
Assignment
The task evolved gradually. This type of structure is often subject to stereotypes. There is a frequent tendency to turn it into a museum; even when repurposed, the historical reference remains strong. The usual result is a short 10-minute visit. Experience-based accommodation with a reasonable standard became the goal—an architectural response without an intrusive attempt to impress or shock at first glance. Taking a hot shower in the depths of a concrete bunker is a unique sensation. The fire pit and terrace are oriented toward the “enemy.”
Surroundings
An unsurprising approach of clearing debris led to surprising discoveries—findings that changed the game. The bunker is located 17 meters from the highway. A normal conversation is only possible by raising your voice. The original direct firing slit toward the border was concreted over and buried. Historical documentation suggested its existence, but it was only confirmed during excavation. On the opposite side of the highway, a small atrium with a terrace and fire pit was created. The new activity around the bunker was great news. The concrete walls of the atrium revealed original camouflage patterns. The excavated soil was used as an embankment, creating a border between the bunker and the field. Protective greenery is proposed, blending subtly with wild vegetation. As the greenery grows, the island in the field comes to life. An outdoor shower and latrine are hidden in the bushes. The bunker’s roof is a small hill offering wide views: the Kamzík TV tower at the foot of the Little Carpathians, the unique Petržalka district, the wind turbines of Upper Austria, and the never-ending stream of cars on the D2 highway.
The Bunker
The interior was not meant to replicate its military purpose or to become a dramatic architectural intervention. The project was a dialogue between the architects, the gradually uncovered reality of the structure, and Martin Kleibl from the civic association Konduktor, which deals with the cultural values of Petržalka.
The massive concrete was stripped down to its core. Only the essential furniture necessary for survival was designed. Beds are inserted as fixed levels between the walls. The base is galvanized steel, topped with solid wood to anticipate less-than-ideal conditions and allow easy repairs. The kitchen island follows the same structure as the beds—a steel frame with a wooden countertop, with the rest left free-form. A few wall anchors allow the hanging of sleeping nets. The bunker can accommodate 6 to 8 visitors. Blue water filtration tanks in the kitchen are mirrored in steel shelves of the same color. External concrete shell casings were repurposed to collect greywater from the indoor shower and kitchen.
