Zagreb, Croatia — In contemporary residential architecture, the prevailing challenge often lies in conquering the landscape—flattening slopes, clearing native foliage, and imposing a geometric will upon the natural world. However, a striking new project in the Croatian capital demonstrates an entirely different philosophy. Designed by the architectural practice FORVM, the aptly named "Curious House" transforms a steep, densely vegetated hillside site in Zagreb into a layered domestic landscape. Here, architecture, extreme topography, and existing mature trees do not merely coexist; they actively shape everyday life together.
Captured through the lens of architectural photographers Bosnic+Dorotic, the project has quickly garnered international attention for its sensitive yet daring integration into a challenging suburban terrain. Rather than viewing the sloping, tree-heavy plot as an obstacle to be engineered away, FORVM treated the site’s natural irregularities as the foundational logic of the design. The result is a multi-level spatial experience that blurs the boundaries between interior living and the rugged, verdant environment of Zagreb.
1. Main Facts and Project Overview
The Curious House is a masterclass in contextual site-responsive architecture. Situated on a steep topography characterized by dense vegetation, the residence relies on a careful balancing act between structural engineering and landscape preservation.
Project Name: Curious House
Architectural Practice: FORVM
Location: Zagreb, Croatia
Photography: Bosnic+Dorotic
Core Concept: Integration of a residential program into a steep, densely vegetated slope, utilizing the existing topography and mature trees to dictate the spatial layout.
At its core, the design rejects the traditional notion of a house sitting on a landscape. Instead, the Curious House inhabits the slope in tiers and fragments, engaging in a continuous dialogue with the ground plane. The layout orchestrates views, regulates privacy, and frames the surrounding greenery as an active participant in the interior spatial narrative. Warm wood finishes, expansive glazing, and restrained material selections allow the architecture to recede, placing the natural topography and mature flora center stage.
2. Chronology: From Slope to Sanctuary
The realization of a project as complex as the Curious House requires a meticulous, multi-phase journey from raw land to completed architectural statement. While the final unveiling took place in late 2026, the project’s genesis spans years of careful planning, environmental analysis, and precise construction execution.
Phase One: Site Analysis and Environmental Mapping
Long before the first foundation was poured, FORVM conducted an extensive survey of the Zagreb hillside. The primary objective was mapping every mature tree and analyzing the precise hydrological and geological vectors of the steep slope. Rather than clearing the plot to create a clean slate, the architects mapped the "voids" between the trees, determining how a multi-level structure could weave through the existing forest canopy without necessitating mass deforestation.
Phase Two: Conceptual Design and Topographic Interventions
The design phase focused on breaking down the programmatic requirements of a modern home into staggered volumes. By terracing the living spaces, the architects avoided massive retaining walls that would alter the natural flow of the terrain. The house was conceived as a series of cascading platforms, each stepping down or climbing up the hill to mirror the natural contours of the Zagreb landscape.
Phase Three: Structural Engineering and Material Staging
Building on a steep, vegetated slope presents severe logistical hurdles. The construction phase demanded specialized micro-foundations to protect the root systems of surrounding trees while ensuring structural stability against soil shifting. Prefabricated elements and targeted concrete pours minimized heavy machinery disruption on the delicate site.
Phase Four: Interior Integration and Completion
Once the concrete and timber skeleton was secured, the focus shifted to the interior landscape. Large-scale glazing was strategically positioned to capture framed views of the canopy, turning the changing seasons into a dynamic interior wallpaper. The final architectural photography by Bosnic+Dorotic documented the completed home, capturing the delicate interplay of dappled sunlight, raw wood textures, and the surrounding greenery that defines the project today.
3. Supporting Data and Architectural Analysis
To truly understand the brilliance of the Curious House, one must examine the specific strategies FORVM employed to address the dual constraints of steep topography and dense foliage.
Spatial Stratification and Sectional Design
Because the site drops sharply, a conventional single-level floor plan was impossible. FORVM utilized a split-level sectional strategy. The house is divided into zones that anchor themselves to different elevations of the hill.
The Lower Tier: Interacts directly with the ground level, housing utility spaces and private retreats that feel embedded within the earth—reminiscent of a modern grotto.
The Main Living Area: Elevated to catch the middle canopy layer, this zone serves as the social heart of the house. Featuring an open-plan kitchen, dining area, and living room, it extends seamlessly onto outdoor terraces that hover just above the sloping terrain.
The Upper Tier: Reaches toward the treetops, offering private bedrooms and study spaces with panoramic vistas of Zagreb.
Materiality as a Mediating Layer
The material palette chosen by FORVM plays a critical role in bridging the gap between raw nature and human habitation. Exterior cladding utilizes natural timber that is expected to weather gracefully over time, echoing the bark of the surrounding trees. Inside, warm wood flooring and minimalist millwork contrast with expansive floor-to-ceiling glass panes. These transparent boundaries ensure that the inhabitants never feel disconnected from the outdoors, regardless of the weather.
4. Official Perspectives and Architectural Intent
According to the design team at FORVM, the primary objective of the Curious House was to challenge the standard suburban development model prevalent in many European capital cities, where hillsides are often stripped of their ecological identity to make way for standardized housing blocks.
"Architecture on a steep, vegetated site should never be an act of dominance," notes the design rationale provided by the architects. "Instead, it must be an act of listening. The Curious House was born from the contours of the land and the positions of the trees. Every decision—from where the walls are placed to how the rooflines angle—was dictated by the desire to preserve the integrity of the living landscape."
Urban planners in Zagreb have also pointed to the project as a positive example of hillside preservation. By working with the natural drainage patterns and root systems, the house minimizes the risk of soil erosion—a common hazard in over-developed sloping districts. The architects successfully demonstrated that high-end contemporary residential design can enhance, rather than compromise, fragile suburban ecosystems.
5. Implications for Future Residential Design
The completion of the Curious House carries significant implications for the future of residential architecture, particularly in topographically challenging regions across Southeastern Europe and beyond.
Redefining Luxury in Topography
For decades, luxury real estate on hillsides often meant engineering a flat pad on top of a flattened slope—essentially erasing the very feature that made the location desirable. The Curious House champions a new definition of luxury: one defined by immersion, bespoke spatial complexity, and ecological sensitivity. Living in a home that responds dynamically to a slope offers a daily spatial richness that a flat, uniform suburban plot can never replicate.
Environmental Stewardship in Micro-Architecture
As urban sprawl pushes development further into forested hillsides and natural buffers, the methods pioneered by FORVM offer a sustainable blueprint. By demonstrating that a home can be woven through a forest canopy without destroying it, the project sets a high benchmark for low-impact hillside construction. Future architects looking at constrained, tree-heavy plots will likely reference the Curious House as a textbook case of how to minimize site footprint while maximizing spatial experience.
A Landmark for Zagreb’s Architectural Scene
Locally, the project cements Zagreb’s growing reputation as a hub for thoughtful, contemporary design. While historical architecture often dominates discussions of the Croatian capital, works like the Curious House prove that a new generation of local practices is capable of producing world-class, critically acclaimed architecture that speaks an international design language while remaining deeply rooted in its specific geographical context.
Conclusion
The Curious House by FORVM is far more than a striking single-family residence; it is a meditation on how humans can inhabit the earth more gently. By refusing to tame the Zagreb hillside and instead choosing to dance with its contours and trees, the architects have crafted a domestic landscape that is as intellectually stimulating as it is visually breathtaking. As it takes its place in the architectural canon, this curious home stands as a compelling reminder that the best design solutions are often found by listening to the land itself.
