Giftshop catering to cryptozoologists and anyone with a sense of humor.

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

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

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

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.

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

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

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.