The Smithsonian announced its ambitious plans to renovate the South Mall section of the National Mall in Washington, which will come with an estimated price tag of $2 billion.

This Master Plan, as the Smithsonian calls it, will take place over a 10 to 20-year period that starts in two years. It was designed by the Bjarke Ingels Group.

They have set out three major goals for the plan: improving visitor services; creating connections between the museums and gardens; and updating old mechanical systems in the buildings.

Most importantly, the plan includes renovating the Smithsonian Castle, starting with a restoration of the Great Hall. A two-level underground space is also planned, which will include a shop, a cafe and visitor services.

“The Master Plan provides the first-ever integrative vision for the South Mall,” Wayne Clough, Secretary of the Smithsonian Institution, said in a statement. “Bjarke Ingels Group has given us a plan that 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 $2 billion will be paid through a mix of federal and private funds as the project continues. It still has to be approved by the National Capital Planning Commission.

Next month, there will also be a public meeting to show alternative plans for the South Mall.

There are 19 museums and galleries under the Smithsonian banner, as well as the National Zoo and nine research centers.