As seen from the sky, this building, designed by the Swiss architects Herzog & DeMeuron, is a perfect equilateral triangle with 180 m long sides and a height of 25 m, suspended on pillars. Geometric spaces, changing tones depending on the light, glass doors and a metallic kaleidoscopic interior are some of the qualities that make up this building’s strong personality. The shape of the courtyards emerges from the juxtaposition of the two urban design elements of the Cerdà Plan and the stretch of road that is the Diagonal. Its rough blue facade is crisscrossed by different strips of glass that suggest the idea of water running down from the roof. The interiors of the auditorium and exhibition halls are designed to be hybrid spaces. The capacity of the Auditorium is 3,084 people.