Situated in the large fun park in the suburbs of Sofia, Radionica Arhitekture‘s proposal for the Collider Activity Center, which won one of five first prizes, is a small artificial ‘mountain’. When external conditions are favorable, the facade opens and the internal atmosphere becomes external. The second layer is the hall, a kind of a “cytoplasm”. The space between the façade and the climbing surface.This is the place of entrance, where the building and the park mix, the site of overlapping where all paths intersect. More images and architects’ description after the break.