The new expansion inaugurated in 2006 has not failed to draw public admiration despite the discretion of Renzo Piano's intervention in the complex.
The new spaces are partly underground, in a return to the oldest traditions of conservation in which precious things were kept hidden but their presence was advertised on the outside with some kind of sign or indication. The underground volume houses the library's most precious treasures, with sophisticated climate control systems, as well as a large 299 seat auditorium.
But the heart of the new complex is the plaza between the old buildings, linking together the library's three separate parts. This space, which is covered-over but very brightly lit thanks to the use of glass and steel, is not just a place to stop but an optimised route between wings of the library.