Collider Activity Center
 LocationSofia, Bulgaria
 TypeCompetition entry  
 Year2013
 StatusCompleted. Unawarded 
 SPOPeopleLara Lesmes, Fredrik Hellberg, Amid.Cero9 
Space Popular. Collider Activity Center. Site


Design for the Collider Activity Center, the new meeting place for all active people in Sofia, Bulgaria. The center includes climbing area, boulder room, multipurpose sports rooms, fitness, spa, swimming pool, offices, restaurant and bar.

Our proposal circles around the imagery of natural rocks, not only in terms of its texture, colour and morphology but as well the space that these provide and the ways in which, in some cases traces of human manipulation are present (the so-called rock-cut architecture). The parallel is very direct, and such was the intention. 

The building presents itself to the user as a cracked prism of soil that has been extracted from the ground and contained in a pristine glass box. The cracked walls provide spaces for climbing and bouldering as well as halls of unimagined proportions. Within the rock’s mass, all the programs hide, only revealed by some openings in the form of rock-cut Byzantine style architectural façades as found in ancient Bulgarian architecture. 

To the exterior, the cut through the rock’s mass is a translucent LED screen that allows filtered light through and, when it is off, brings the illusion of the solid mass it is representing, but, when on, it plays everything from the latest Walltopia graphics to bouldering competitions taking place inside the building or elsewhere in the Walltopia centres across the globe and even advertisement during the breaks. 

The building roof is covered in solar glass, which lets light in and collects energy all year around to power both the swimming pool and the LED screen. Both the roof and the facades have louvers for ventilation, creating drafts through the cracks when opened. 

The constructed prism is and 80 by 25 meters skewed rectangle, adjusting to the shape of the plot and creating oblique angles towards the view of the Vitosha mountain, thus maximising the spaces that would get such sight. 28 meters heigh, the prism sinks 6 meters above ground level, gaining some surface area that allows for greater halls in the interior and creating a sense of discovery at arrival. 

Approaching from the south side we would see the elevated winter garden that connects to the rooftop bar in the south sharp corner of the building, below which the frenetic activity of the Funtopia hall takes place. The swimming pool is revealed only when we are a few meters away from the building, since it is sunken 3 meters below ground. The ongoing activity at the deep solo climbing area over the pool and the restaurant around it provide an exciting first sight of the Activity Center and, given the gentle slope in the building’s perimeter, views of the Vitosha mountain are found from the restaurant’s outdoor area. But if, instead, we are coming from the north side, we would cross the park, surrounded by climbers practicing in the Ropetopia attractions or the outdoors boulders that seamlessly blend with the main interior bouldering hall on the north side of the building and, only when we are a few meters from entering, we discover the multifunction hall that, with a height of 6 meters, sinks in the terrain letting the slope create natural outdoor seating for summer shows in the hall. 

Once inside the building, no pillars interrupt the halls, since all structure above ground level is hanging from 2 pairs of massive beams supported by 4 heavy duty concrete supports that perform as communication knots for vertical circulation inside, 2 of them contain elevators and the other 2 staircases for firescapes. From the elevator cores we access the fitness and spa, the office spaces, rooftop bar, etc., all of them only revealed towards the climbing halls as rock-cut Byzantine style openings, emphasising the illusions of being surrounded by massive rocks from the crack and providing singular and perhaps even surreal moments in the programmed spaces behind the climbable rock-like walls. The pink floor mats in all climbing halls also enhance the unreal feeling by inserting a contrasting element to the, otherwise, natural looking environment, and the reflections on the walls brings spatial variation and dynamism to the space.

The intricate geometry of all spaces gives a constant sense of discovery into a building whose main purpose is to provide us with adventures. 





Interior of climbing crack. SPOP. Collider Activity Center




























Space Popular. Collider Activity Center. Plans



Space Popular. Collider Activity Center. Exploded FacadeSpace Popular. Collider Activity Center. Elevation. LED facade
Space Popular. Collider Activity Center. Elevation LED Facade
 Space Popular. Collider Activity Center. Elevation LED Facade


Space Popular. Collider Activity Center. Section. EW
 Space Popular. Collider Activity Center. Section NS

Space Popular. Collider Activity Center. Section WE






































Space Popular. Collider Activity Center. Portals in the rock































































































 Space Popular. Collider Activity Center. View. Coffeeshop

Space Popular. Collider Activity Center. View. Main Climbing Space