Crystal is an up-to-date office building in the true heart of a sought after location of Prague Vinohrady. It stands out because of the extraordinary architecture (Atelier 15 under Libor Hrousek and well-known Radek Lampa) and meets the strict energetic class A. From technical view, Crystal has got a very demanding curtain-wall construction based on 3D designing (Inventor 3D) and space modules. There were 1300 modules of 275 different types used with 16 atypical W8 modules. The total 6.000 m2 chess-board curtain-wall consists of aluminium Alucobond panels and 2.800 m2 glassed surface.