A master plan to renovate and improve the South Mall campus of the Smithsonian Institution was revealed with an estimate of $2 billion. The centerpiece of the project would be a revitalization of the "Castle," the signature building that holds administrative offices of the Washington, DC, institution.

Visitor services, a café and shop, with direct access to the Enid A. Haupt Garden and the underground Ripley Center, would be added to the Castle. Also, the project includes new Mall-facing entrances to the National Museum of African Art and the Arthur M. Sackler Gallery; and improved visibility and access from the Freer Gallery of Art to the Hirshhorn Museum and Sculpture Garden. 

Architect Bjarke Ingels of BIG, the Bjarke Ingels Group, says the plan is "an example of radical reinterpretation."

The proposed Master Plan combines several major projects, some of which address known infrastructure needs, including leaking roofs, failing mechanical systems and inefficient energy use.

Wayne Clough, Secretary of the Smithsonian Institution, said the plan “...will offer open vistas, connected museums, galleries bathed in daylight, new performance venues, gardens that invite people into them, and it will visually attract visitors who will have an unparalleled experience.”

The initial cost estimate is about $2 billion, to come from a mix of federal and private funds, over the course of the project, says the Smithsonian. The project would start in 2016 and take 10-20 years.

A public meeting will be held in December. The plan would need review from National Capital Planning, and secure funds from Congress and private sources.