subtilitas:

Diener & Diener - New east wing of the Museum of Natural History, Berlin 2010. After being nearly destroyed by bombing during WWII, the architects took a unique approach to its reconstruction and preservation. Using silicon taken from the surviving exterior shell, a replication of the existing facade was cast in concrete, down to the detailed level of each individual brick. Due to the light-sensitive nature of the exhibits within, some existing windows were bricked up, and the new concrete cast windows were given the original mullion details. The result is an interesting patchwork highlighting the building’s history; a dialog between it’s original form, destruction, and reconstruction. Image via.

been here.  its even better in person.