This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

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

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

The iconic D.C. restaurant where the Cuban Missile Crisis was negotiated, now a Walgreens.

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

An obscure federal monument honors the French diplomat who served as Ambassador to the U.S. during WWI.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

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

"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!”

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

Where the U.S. government kept its actual treasure, before Fort Knox.

A wondrous old library overlooking the nation's capital.

A historic arena where the Beatles played their first concert in the U.S.

A diminutive memorial marks the site of a successful assassination by a right-wing death squad in America's capital.

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

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

A much-maligned monument to teetotalism.

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

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

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