Between the First and the Second World War, a defensive line of bunkers were built along the border of Austria and Hungary to prepare for a battle that never happened. In the 1930s, Czechoslovakia invested in these military fortifications to defend against Nazi Germany, which eventually threatened Bratislava, sitting miles away from the Austrian border. The design of these border defenses at the time were state of the art and a direct result of French cooperation. However, in 1938, Czechoslovakia had to give up most of its borderlands under the Munich Agreement, soon after which it fell under Nazi control.

Scattered across Petržalka, a residential district of Bratislava that was built during the communist era in the former Czechoslovakia, now Slovakia since 1993, 14 bunkers have remained somewhat preserved. While some of these bunkers were converted into museums, often operated by history enthusiasts, the others were left abandoned. Among these edifices, Bunker B-S 10 was discovered along the highway. Contrasting with other B-S bunkers in the region, the discovery led to the introduction of a unique programme transforming it into an experiential accommodation. TOITO architekti, a Bratislava-based Slovak architecture practice channelled the history of the bunker architecture for the adaptive reuse project, establishing strong connections with the surrounding natural landscape. Martin Kleibl, a cultural activist fascinated by Petržalka, collaborated with the architects to oversee the execution of the renovation, eventually assuming the responsibility of the property’s operation.

Built between 1934 – 35, the bunker underwent several structural renovations over the early years of its existence. Originally designed to accommodate 10 soldiers, the partially buried 1.5-metre-thick reinforced concrete shell was equipped with two heavy machine guns, along with a mechanism to throw grenades outside the defenders’ line of sight. A small opening on one of the walls was created to place the rotating turret of a light machine gun, but later covered with concrete to leave space for a periscope. Later, the bunker incorporated a pedal-powered ventilation system based on a bicycle mechanism. Having never actually witnessed combat, the highway-adjacent bunker remained hidden until it got noticed in 2017.

Designed to accommodate six to eight visitors at once, Bunker B-S 10 distinguishes itself from other bunkers in Petržalka which, as TOITO architekti tells STIR, “have been restored to their original appearance, with artefacts from the respective historical period on display. B-S 10 respects the utilitarian function but does not seek to merely replicate it visually.” The bunker is quietly nestled within the natural landscape with the help of a self-seeded green roof, which also acts as a barrier to protect the users against the noise from the road. Foregrounding its raw, unfinished concrete architecture with a compact winged footprint, the architects incorporated functionality-oriented interventions within and around the bunker.

The outdoor features comprise a shower along the front facade, a fireplace and a seating space facing Slovakia’s border, a reminder of the independence the nation now thrives in. “The bunker is fully self-sufficient—water comes from a well, photovoltaic panels provide electricity and a composting toilet sits in the front, next to the outdoor shower,” the design team adds. The off-grid architecture also features water filtration tanks in the kitchen and a greywater collection system in the indoor shower and kitchen, built using external concrete shell casings.

The experiential design stages almost a hauntingly beautiful living environment within the militarily redundant shell, echoing the tensions and horrors of war. The pipes, running unapologetically along the imperfect, aged surfaces and the bright white lights stage a cold, unsettling environment, reflecting the piercing temperatures the region often experiences. The bespoke galvanised steel and spruce wood furniture designs follow a utilitarian language to complement the concrete architecture, almost uncomfortably occupying the compact residential interiors of the bunker. “The separation of new and original layers is characteristic of the project…the original structures are exposed without coatings and new elements, such as the kitchen, beds and shelves, are functional, durable and austere,” the architects continue. The interior design follows a distinct, utilitarian language of design, featuring steel bases and frames topped with wooden surfaces that are suitable for prolonged use.

By neither romanticising nor erasing its past, TOITO architekti’s intervention insists on the continued presence of historical memory in the present. Architecturally restoring the bunker to its original state, the project transforms the cold, silent and redundant bunker walls into carriers of an experiential contemporary living. In its journey from a defensive outpost to an experimental dwelling, the bunker becomes a paradox: a space built to participate in and withstand war, now repurposed into a shelter 32 years into the country’s independence.

Project Details

Name: Bunker B-S 10
Location: Bratislava, Slovakia
Architects: TOITO architekti
Year of Construction: 1935
Year of Renovation: 2024
Built-up area: 90 sq m
Service area: 34 sq m