Designed by Madrid-based architecture practice BETA.Ø, Casa X is a private residence in the El Viso neighbourhood of Madrid. The project transforms an existing house into a contemporary home organised around a sculptural X-shaped staircase, which connects three levels and brings natural light into the heart of the building.

The architectural intervention establishes a close relationship between interior and exterior spaces. Large openings, terraces, a garden and a rooftop swimming pool extend the living areas beyond the building itself. Exposed concrete, wood-cement flooring and restrained finishes contribute to an atmosphere defined by geometric clarity, natural light and material continuity.

The interiors combine custom-designed furniture by BETA.Ø with twentieth-century design classics. The living room brings together the LC4 chaise longue by Le Corbusier, Pierre Jeanneret and Charlotte Perriand for Cassina, original Chandigarh armchairs by Pierre Jeanneret, and the Extrasoft sofa by Piero Lissoni for Living Divani. A Cestita lamp by Miguel Milá for Santa & Cole introduces a softer domestic presence alongside the architecture's precise lines.

Art plays an equally important role throughout the residence. Works by Carlos Evangelista, Manuel Salinas, Luis Canelo and Waldo Balart appear alongside photography by Aitor Ortiz. In the study, a marble table by Angelo Mangiarotti is accompanied by drawings by Eduardo Chillida, while works by Luis Tomasello and lighting by Michael Anastassiades define the character of the adjoining office.

Photographed by Daniel Schäfer Studio and published in Architectural Digest Spain, the editorial series documents the relationship between architectural geometry, contemporary interiors, art and design, revealing the distinctive spatial character of Casa X.