The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

An ear-piercing buzzer calls lawmakers to a vote with a series of long and short rings to form coded messages.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

The United States Capitol's former columns still stand.

Home to items never before seen by the public.

Before Metro, Washington had a robust streetcar network—and you see the remains of this infrastructure if you know where to look.

The site of the climactic scene from the classic horror film is now a historic landmark.

A secret greenspace hides atop a Capitol parking garage.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

A derelict bit of transportation infrastructure hidden in the woods.