The Capitol Visitor Center is a three-level underground extension of the United States Capitol Building that provides secure entry for visitors and employees. The last opportunity to extend the capitol within the historic framework of the grounds designed by Frederick Law Olmsted, Sr., it is the most significant project at the capitol in the last 150 years. The Sasaki design team worked with landscape historians to develop a plan that preserves or rehabilitates the most significant defining areas of the original Olmsted design including the East Plaza, the two flanking expanses of lawn and trees, and the East Capitol Street axis.
Over 95% of the building footprint is located below the paved areas to preserve existing plantings. A series of steps and sloped walkways for universal access provide clear orientation for tour groups and individuals alike, leading to the capitol's entry at the Visitor Center. These additions to the historic capitol grounds are sited to avoid significant historic landscape zones.
While the Visitor Center project enhances security with screened entry and perimeter security, the capitol grounds are actually made more accessible by opening the East Plaza up to pedestrians. Sasaki restored historic fountains, walls, seating, and lighting and planted trees, shrubs, vines, and ground covers to replace plantings that were overgrown and in decline. Sasaki used historic documentation of the planting to define the original intent, materials, and view corridors—all designed to amplify the distinctive capitol setting.