Hear ye, hear ye! The Smithsonian’s “Castle” is closing.

Not for good, though—don’t worry. The Smithsonian Institution Building, a.k.a. the Castle, is closing for a much-needed renovation on February 1. The repairs and upgrades to the 1850s building—the Smithsonian’s first home—will be the most substantial in five decades, with elements across the structure getting a top to bottom refresh.

Designed by James Renwick Jr. and completed in 1855, the National Historic Landmark–listed property houses the Smithsonian’s Visitor Center, a gift shop, cafe, an a small survey display of items from the collection, while the nonpublic spaces largely serve as the Institution’s administrative headquarters. While the buildings fabulous Seneca sandstone looks more or less the way it did in Renwick’s time, the interior has undergone many alterations over the years that didn’t always complement the original design.

This upcoming round of renovations will restore the Great Hall to its original appearance and height by removing an interstitial floor of office space installed in the hall during its last major renovation in the late 1960s. This will allow the Upper Great Hall to become a venue for programming, as it was before the midcentury addition. The gift shop, cafe, and restrooms will be relocated to the lower level. This round of upgrades will also restore windows and install new ones where needed, restore the roof and stonework, replace the mechanical, electrical and plumbing systems, and upgrade IT systems, among other improvements.

Pedestrian access from the National Mall to the National Museum of African Art will be preserved during the five year construction project, and the property’s Enid A. Haupt Garden will be remain open.

A virtual Visitor Center will debut early next month to help orient both in-person and remote visitors to the Smithsonian’s many museums and exhibitions. Among the other projects currently under the Smithsonian’s purview are the recently remodeled, partially reopened National Air and Space Museum and planning the future locations of the National Museum of American Latino and the Smithsonian American Women’s History Museum. In late October, the institution selected two “optimal” sites for the forthcoming museums in the nation’s capital.