Ronald Reagan Building and International Trade Center

The Federal Triangle is the wedge of land between Pennsylvania Avenue, Constitution Avenue and 14th Street. In the early twentieth century, city planners, architects and federal officials set out to realise Pierre L'Enfant's plan for the capital; eight monumental buildings rose between 6th and 15th Streets, and then the Depression stopped construction. The last parcel remained a parking lot for more than fifty years.

In 1987 Congress passed the Federal Triangle Development Act, authorising a federal complex and an international cultural and trade center to finish the redevelopment of Pennsylvania Avenue. In 1989 the architects were picked: Pei Cobb Freed & Partners (New York), working with the Washington firm Ellerbe Becket. Building work started in 1990. The name came in 1995, when Congress unanimously chose to honour President Reagan, the signer of the enabling act; the building was dedicated on 5 May 1998.

At Pei Cobb Freed & Partners, which served as lead architect to the Delta Partners development group, the design team was headed by James Ingo Freed. The building's footprint covers roughly seven acres and its perimeter exceeds half a mile; among federal buildings, only the Pentagon is larger. Maximum height limits meant it had to be designed from the top down; a very shallow water table made the below-ground parking levels harder to build. It has five levels below ground and nine above. Its diagonal layout responds to the eastward bend of Pennsylvania Avenue toward the Capitol: set square to the avenue, the building turns back from a rotunda on the corner.

The exterior was drawn to match the neoclassical style of the neighbouring buildings of the 1920s and 1930s, while the interior takes a contemporary plan. The structure is mostly concrete; the central atrium's glazed roof rests on steel beams bent into half-circles. In the nine-level atrium, two curved metal curtain walls carry Route Zenith, a glass and neon work by Keith Sonnier made in close collaboration with Freed: it stands 49 feet high and 30 feet wide, made of glass plates and neon tubes in red, blue and yellow.

Owned by the General Services Administration and run by Trade Center Management Associates, the building houses federal agencies, public and private bodies, and shops. Designated as the official World Trade Center of Washington, it holds a conference and event centre, offices, shops and restaurants, including a food court. Bearing Witness, a 40-foot bronze sculpture by Martin Puryear, stands on Woodrow Wilson Plaza; by the building's Woodrow Wilson Plaza entrance, a large section of the Berlin Wall is on permanent display.

The building is open every day of the year, from 5 a.m. to 2 a.m.; as this is a federal building, every visitor goes through a security check. Six pedestrian entrances lead in, one of them at Metro level: Federal Triangle station is on site, linked to the building by a covered passage.