London architecture firm Foster + Partners and Madrid firm Rubio Arquitectura are slated to overhaul the Museo del Prado, the most important museum of art in Spain. The project involves reorganizing the floors and replacing the roofs of the 17th century Hall of Realms, an extension off of the Museo del Prado.
The Hall of Realms is actually older than the museum itself. Originally, the building at that location in Madrid was a palace (and the Hall of Realms was a wing of said palace.) The Museo del Prado was built later, in the 19th century. As such, the Hall of Realms is especially in need of repairs.
The architects will build two major changes. First, the layout of the floors inside will be adjusted to add more room for artwork. Second, the firms will incorporate solar cells into a new, modern roof.