There’s a hidden military meme engraved on the World War II Memorial.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

An Industrial Revolution-era public work that purified water using nothing but sand.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

People escaping slavery may have hidden inside a corpse vault.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

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

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

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

A wondrous old library overlooking the nation's capital.

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

This grand gothic brewery has been pumping out suds for over a hundred years.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

Proto-CIA agents trained with grenades in the sand traps and fired machine guns from the fairways.

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.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

The most accurate timepiece in the world.

A painfully obvious spy house sits right across the street from the Russian Embassy.

Narrow gorges and deep pools created by long-ago glaciers.

A winding, cliffside stretch of road overlooking the Delaware River.

This old-fashioned candy shop, ice cream parlor, and diner served as the setting for one of TV's most controversial series finales.

This Hollywood dive houses a mural painted by the artists who animated its namesake film.