An heir to the Giant Food fortune built this Forest Hills single-family in 1994 to house his art collection. According to a 2015 listing, the building pays tribute to English architects James and Robert Adams. The Kuwaiti government bought it the following year for $18 million. 

The 16th Street Bridge was the first parabolic arch bridge constructed in the U.S.

It spans 272 feet, and is made of reinforced concrete and steel with hollow spandrels between the arch and abutments. It's also known as the Piney Branch Bridge. Construction wrapped in 1910.

The Ashburton House is also known as the St. John’s Church Parish House or British Legation.

Built in 1836, it served as a home for British diplomats, and was the site of 10 months of U.S.-British negotiations that eventually led to the Webster-Ashburton Treaty of 1842. It is currently used as offices and meeting space for St. John's Church.

The building has been heavily renovated, but still includes original details such as the six marble- and one wood-mantled fireplaces, four floor-length marble columns on the first floor, and lintels above the doors.

Built in 1800, the White House might be the most well-known neoclassical building in America.

It was designed by architect James Hoban to resemble the Leinster House in Dublin. George Washington wasn't so keen on Hoban's Georgian-style submission, so he requested the development be widened and more ornamental.

In 1824, architect Benjamin Henry Latrobe added the portico to the building and is said to have been influenced by the Château de Rastignac, a country estate in France.

The Treasury Building was built in four phases from 1836 to 1869. It was declared a National Historic Landmark in 1971, and serves as the headquarters for the U.S. Department of the Treasury.

It features a three-story-high ionic colonnade and a full entablature unbroken by a pediment.

According to the GSA website, the GSA building was the first truly modern office building that the U.S. government constructed. It served as a model for federal offices through the early 1930s.

Built in 1917, it was the first federal building to use limestone facing. The building features an E-shaped plan allowing for open courtyards.

The building dates from 1908, and houses the offices and chambers of Washington’s mayor and City Council. Philadelphia firm Cope & Stewardson won a competition to design the structure. 

John Russell Pope designed this 1929 building. 

Housing D.C.’s largest auditorium and designated a National Historic Landmark in 1985, the DAR Constitution Hall was originally built to host the Daughters of the American Revolution’s annual convention.

The Commerce Department’s headquarters includes Indiana limestone walls, bronze doors, a Vermont marble base, and accent flooring. 

When built in 1932, it became the largest office building in the world with with more than 1.8 million square feet of floor area, forming almost the entire west side of the Federal Triangle from Constitution Avenue to E Street.

The Capitol was designed to resemble an ancient Roman temple, and construction would last from the 1790s well into the 20th century as the federal government expanded the complex and added its famed dome. 

Built in 1932, the Arlington Memorial Bridge is a stone arch bridge composed of masonry, steel, and a central bascule that crosses the Potomac River.

It spans 2,163 feet, and was listed on the National Register of Historic Places in 1980.

Designed by architect John Russell Pope, the memorial features circular marble steps, a portico, a circular colonnade of ionic order columns, and a shallow dome.

To build the memorial, Pope made references to the Roman Pantheon and Jefferson’s own design for the University of Virginia’s rotunda. Construction wrapped in 1943.