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Pumice Walls Crafted at the Intersection of Tectonic Plates

Authors:
Micah Sexton, Emily Sexton
Pumice Walls Crafted at the Intersection of Tectonic Plates
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Constructed with pumice walls at the tectonic intersection of Eurasia and North America, the tower serves as a visitor center that enhances engagement with the geothermal landscape of Grjótagjá.
5 key facts about this project
01
Constructed directly on the fault line between the Eurasian and North American tectonic plates.
02
Utilizes pumice-based concrete for both structural integrity and ecological sensitivity.
03
Includes a private bath cave that integrates with the natural geothermal landscape.
04
Features a multi-functional visitor center with an observation deck overlooking geothermal pools.
05
Incorporates interpretive signage to educate visitors about the site's geological history.

The Iceland Cave Tower is located at Grjótagjá, a site known for its unique geological features like volcanic rock and geothermal pools. Positioned along the fault line between the Eurasian and North American tectonic plates, the tower serves as a monument that represents the connection of these two landmasses. The design highlights a relationship with nature, inviting visitors to experience the landscape while providing essential services.

Architectural Concept

The design focuses on the geological context of the site. The tower acts as a central point that encourages exploration and interaction with the geothermal features beneath it. The form reflects the earth's elements and the geography around, creating a space that resonates with the natural forces at play.

Functional Layout

Visitor facilities are incorporated into the design, including restrooms, a visitor center, an observation deck, a café, and a private bath cave. This layout addresses the practical needs of visitors while enhancing their connection to the surrounding landscape. The visitor center serves as an information hub, positioned to provide outdoor seating that offers views of the geological formations, allowing patrons to enjoy both the architecture and the scenery.

Materiality and Construction

Pumice-based concrete was chosen for the tower's construction, demonstrating a focus on durability and ecological considerations. The overlapping scale walls add structural strength while echoing the natural shapes in the environment. This material choice reflects a commitment to sustainability and an awareness of the site's characteristics.

Design Details

Careful planning has gone into the circulation paths that allow visitors to navigate the site. These paths guide visitors while featuring interpretative signage that explains the history and formation of Grjótagjá. This approach creates a narrative that connects the building to its geological context, enhancing the visitor experience. The design underscores the importance of the geothermal pools, focusing on both engagement and education through the architecture.

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The Buildner’s Unbuilt Award 2025 is an international architecture competition dedicated to recognizing and celebrating the value of unrealized architectural designs. It invites architects, designers, and students worldwide to submit visionary projects that have not yet been constructed, highlighting the power of ideas and the creativity behind the design process. By focusing on unbuilt work, the competition aims to bring forward concepts that shape the future of architecture and push the boundaries of the profession. 

Participants can compete in three categories based on project scale: Small Wonders (up to 100 m²), Medium Marvels (101–999 m²), and Large Visions (over 1,000 m²). Each category winner will receive €20,000, and additional prizes include honorable mentions, student awards, and a special Best Presentation Award. Winning projects will gain significant international exposure through Buildner’s publicity campaign and a feature article on ArchDaily, providing a unique opportunity to showcase creative ideas to a global audience. 

The Buildner’s Unbuilt Award 2025 encourages entrants to submit any type of unbuilt project, from conceptual visions to detailed designs, celebrating bold innovation without the constraints of realization. Important deadlines: registration closes on October 30, 2025; submissions are due by November 20, 2025; winners will be announced on December 17, 2025.

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100,000€ Prize / 2025 ideas COMPETITION
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