The concept for the library and media center for the Humboldt University in Berlin is generated by its three main site conditions: First the emissions caused by the municipal train viaduct that runs directly to the south of the site, second the landmark views that open up to the east and the west of the site and third the spatial pattern of the typical Berlin-block directly adjacent to the north of the site. We developed a multilayered strategy that reacts to these conditions logically: Towards the train viaduct in the South, the building facade is closed completely, except for the ground floor zone, where the main access is located. The closed facade protects the valued inside of the library and media center. Towards the east and the west, the building opens up completely, allowing a constant visual connection between the major urban focus points of Bahnhof Friedrichstrasse towards the west and the museum-island towards the east. The circulation within the building and the generous interior organization is consequential. The brief asked for a traditional library with a central reading room. We established two reading rooms one for books and another one for accessing more contemporary media. Both spaces are surrounded by books and media on numerous levels. The cubature of the building follows the logical conclusion of the inner-city block structure of Berlin, starting in the south from Kochstrasse at check-point Charly and ending at the site towards the train viaduct in the north. Underneath the train viaduct bars and cafes that extend outside into the gap between the viaduct and the library complement the lively entrance situation at street level. The glazed ground floor, with all public amenities, opens the building towards this important urban space inviting the pedestrian flow of the area into its open interior.