In Northern Spain, the Cantabria province is famous for its caves. Declared UNESCO World Heritage Sites, these geological formations are steeped in rich history and culture, with the most significant being the cave of Altamira whose cave paintings date back to 37,000 BCE. In the region’s capital, Santander, a cavernous new restaurant designed by Madrid firm Zooco Estudio recalls the region’s rocky topography. Located within the Cantabrian Maritime Museum (MMC), the restaurant’s design brings a contemporary sensibility to the building’s brutalist shell.

The complex, designed by Vicente Roig Forner and Ángel Hernández Morales and completed in 1978, also includes an oceanographic research centre. It consists of two square concrete structures connected by a canopy and separated by a central space for public access. In 2003, the building underwent a renovation with an extension to the west façade and a pyramidal aluminum structure added to the roof to enclose the existing terrace.

The three-storey museum is organized around a central courtyard framed by a vault of paraboloid membranes, with the new restaurant and adjacent terrace located on the second floor. Rather than adding to the building, Zooco Estudio sought to embrace what was already there. To that end, they began by attempting to recover the original roof, which was used for water collection. Previous interventions rendered this an impossible task, so the designers instead opted to replace the pyramidal roof with a new one that was watertight and insulated, and the façade with a new curtain wall.

But the museum still had good bones: Zooco stripped back previous paint treatments from the paraboloids to expose the concrete, allowing the geometry of the brutalist structure to be appreciated in its rawest form. The texture of the board-formed concrete, still dotted with traces of pigment, offers a glimpse of the building’s past.

The corners of the restaurant were filled out with an airy slatted oak ceiling that counters the heaviness of the concrete arches. Bespoke oak furnishings echo the wood ceilings, while the grey porcelain floors mirror the concrete structure and aluminum accents round out the minimal palette. The furnishings and lighting aptly draw from nautical references, grounding the restaurant in its coastal context.

While at the restaurant’s core, the structure is massive and imposing, it is balanced by a barely-there glazed façade draped in lightweight sheer curtains. The glazing introduces natural light into the otherwise cavernous space and also provides sweeping views of the Bay of Santander, dramatically framed by the concrete arches. The curtain wall opens up to the panoramic rooftop terrace furnished with ample outdoor seating by HAY.

Given the proximity to the sea and the resultant wind exposure, the façade was designed to be resistant to the marine climate, with a natural aluminum finish selected to blend in with the rest of the material palette. Brutalist buildings often get a bad rap, yet Zooco Estudio has found a way to preserve — and celebrate — the museum’s architectural heritage while ushering its interior into the 21^st century.