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

After his presidency, George Washington planned to live only a few blocks from the Capitol building.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

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

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

A secret greenspace hides atop a Capitol parking garage.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

Home to a vast and influential collection of Shakespeareana.

There just so happens to be a court even higher than the U.S Supreme Court: a basketball court in the building itself.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

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

The walls of the iconic dome are hollow and have a secret stairway.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Corn-inthian columns with a uniquely American take on neoclassical architecture.

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

The tunnel under the Capitol Building where Congress takes out its trash.

An easily overlooked memorial to a Ukrainian famine-genocide that killed over 4 million people.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Suspended above the ground in a thicket of towering Georgia trees is a modern architectural wonder.

Dedicated to the "King of Soul."

Nature (and graffiti) reclaim this old waterworks that has been surrounded by a bike path and network of walking trails.