Adding to the complex conversations that inform and propel the discourse around the 19th Venice Architecture Biennale, Spain's participation lends a comprehensive and fittingly modern response to one of the most pressing concerns of our day: how can architecture and design promote ecological balance rather than jeopardise it? Internalities: Architectures for Territorial Equilibrium, the Spanish Pavilion curated by architects Roi Salgueiro Barrio and Manuel Bouzas Barcala, explores how built environments could reduce ‘externalities’ and act as revitalising agents for architecture, ecologies and economies in Spain. Taking to the overall curatorial impetus of the Venice Architecture Biennale 2025 by Carlo Ratti, Intelligens. Natural. Artificial. Collective., the pavilion design investigates how architecture may respond to the glaring effects of the climate crisis by operating within the practicable constraints and capabilities of its local context rather than by exporting its costs abroad, or over unsustainable distances and geographies. This especially affronts the metric of construction activities being responsible for a significant portion of global CO2 emissions. “Internalities analyses in what ways, to what extent, at what costs, through which buildings, cities and territories, Spanish architecture is leaving behind the economies of externalisation,” the curators Barrio and Barcala state in an official release.

The term ‘internalities’ was devised by the Spanish architects specifically for the architecture exhibition. It is an antithesis to the well-known economic term ‘externalities’ coined by British economist Arthur Pigou in 1920, referring to the indirect costs impacting people and territories not directly involved in the production of a product. Construction generates externalities when materials are extracted, non-renewables are burned, local trades are displaced, waste is produced and emissions are belted out. By designing with ‘internalities’ in mind—lowering emissions, reestablishing connections with local resources and boosting local economies—the Spanish pavilion proposes a model to reverse this equation. “Externalities cause a serious imbalance between the buildings we construct and the territories they affect,” the curators explain. Iñaqui Carnicero, Secretary General of Urban Agenda, Housing and design, further notes, “This project highlights how architecture can contribute to a country's decarbonisation while acting as a driver of economic development, boosting the revival of local economies."

The pavilion, intended to be an immersive, research-driven exposition, organises itself around a central hall, dubbed Balance, serving as a suitable introduction to the project. Two scaled models of each of the 16 architectural projects displayed in the central area—selected for their ambitious and ingenious use of internalities—are positioned on a set of actual balances. Whilst one model showcases building systems from the project derived using the most ‘internalised’ material, the other lays bare the larger geography and geological conditions of the material's extraction and origin. Together, the architectural models underline the exhibition's primary ethos of an equilibrium by illuminating the relationship between architecture and territory. Although the materials and techniques used in these projects vary, from clay and wood to schist and repurposed concrete, they all depict how careful planning may help localise the building process.

The featured projects in the central hall further exhibit how these internalities appear in different contexts, societies and scales. In Ibiza, RAW ROOMS by Peris + Toral Architectes combines density with traditional thermal comfort by using timber, cork and compacted earth in modular apartments centred around courtyards. KAUH's Mediterranean Gardens of La Hoya Park in Almería uses landscape regeneration and dry-stone terraces to restore a historic ravine. Another example of Balearic architecture is Munarq's Ca Na Pau, a courtyard house that frames and shields the countryside using earth ballast. Bosch Capdeferro's 6x6 Block in Girona employs cross-laminated timber to experiment with adaptability in communal housing models and HARQUITECTES' Palma project recycles marés sandstone waste to create waste-free cyclopean concrete walls. Further, Josep Ferrando and associates' Fire Station in Moià utilises prefabricated wood to enhance the transparency of the entire structure, striking a balance between strength and simplicity.

Adjacent to the main hall, five side rooms are devoted to the five axes of decarbonisation: Materials, Energy, Labor, Residues and Emissions. Original research and photographs on display delve into local case studies that highlight the intricacies and possibilities of internalising architecture. Architects Daniel Ibáñez and Carla Ferrer describe the entire life cycle of lumber along the Cantabrian coast—from managed forests to its use in architecture—in the Materials axis. The room demonstrates how wood can serve as a model for more sustainable construction with a low ecological footprint through the work of María Azkarate. Under the direction of Estar (Aurora Armental Ruiz and Stefano Ciurlo Walker) and photographer Luis Díaz Díaz, the Energy axis examines the social and environmental consequences of massive wind and solar farms on the northwest Atlantic coast of Spain. Through research and photographic work, the room pursues harmony between energy infrastructure and the landscape, with the showcase offering an alternative model to that of large wind farms by multiplying production sites and reducing intervention scales.

Together with photographer Caterina Barjau, Anna and Eugeni Bach examine Catalonia's history of earth-based building in the Labor axis. With a focus on companies such as Cerámica Cumella and Fetdeterra, their study emphasises the importance of local techniques, including baked clay, compacted earth and handmade ceramics, as well as the craftspeople who maintain them. The Residues axis moves to Madrid, where Lucas Muñoz and visual artist Ana Amado study mid-century home demolition trash. Madrid is largely dependent on imported energy and materials due to its limited local resources; this research suggests circular building techniques that minimise waste in the future by reusing current materials. Carles Oliver, David Mayol and photographer Milena Villalba showcase projects from the Balearic Islands in the final Emissions axis. The presented work uses compacted soil, posidonia and marés stone, capturing a convincing picture of low-carbon regional building by spotlighting how modern architecture in the Balearic Islands strives for self-sufficiency within the framework of degrowth.

The days of the Vernissage brimmed with substantial public programming, leading up to the anticipated public opening of the Biennale. On May 10, the Spanish Pavilion hosted a conversation including curators and scholars from all five side halls to coincide with the Biennale's inauguration. The methods, conclusions and ramifications of the pavilion's work were examined in greater detail during this programme. The team has additionally created a digital portal that showcases all of the initiatives and includes an interactive map that charts the materials and environments being studied in order to increase the project’s accessibility beyond Venice. “Conceived as a collective and open-access tool for all citizens, this mapping transcends political borders to reveal the Iberian Peninsula as a key productive ecosystem in the country’s decarbonisation process,” the official release reads.

The Spanish Pavilion arrays grounded, location-specific approaches to sustainable building, embracing a plurality in sources as well as processes. It respects territory, accepts complexity and recognises that change is a careful culmination of accuracy, information and consideration. The pavilion seeks to refine the understanding of  sustainability as a spatial and ethical commitment by staging projects that operate within their cultural and environmental surroundings, not just extracting but also dynamically interacting with them. As the climate crisis intensifies globally, the pavilion discursively stands on the other side of grand, sweeping gestures meant to necessitate architectural change, or even fragments of it, instead rallying for a change in viewpoint from extraction to regeneration, from global dependency to local resilience.

The 19th International Architecture Exhibition of La Biennale di Venezia is open to the public from May 10 to November 23, 2025. Follow STIR’s coverage of Venice Architecture Biennale 2025 (Intelligens. Natural. Artificial. Collective) as we traverse the most radical pavilions and projects at this year’s showcase in Venice.