This elaborate towering structure was once famed for its revolutionary height.

The first American department store, and home to the largest operating musical instrument in the world.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

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

The romance of early commercial flight still fills this Art Deco destination.

Largest Roman Catholic church in North America.

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

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

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

The elevator that makes it possible to fly American flags in bulk over the U.S. Capitol

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

At 207 feet, one of the world's longest continuous escalators.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The "lovely red Vega" of the legendary record-settling pilot.

The most accurate timepiece in the world.

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

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

Decades before the scandal, this staircase on the river was a literal "water gate."

Helen Keller once broke ground on this historic center for the study of technologies to benefit the hearing impaired.

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

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