Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

The tragedy of the Japanese internment camps is remembered here by a stark "Soul Consoling Tower."

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

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

People escaping slavery may have hidden inside a corpse vault.

The most accurate timepiece in the world.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

This poor little statue is the most vandalized memorial in Washington.

A remote horde of architectural treasures fit for Indiana Jones.

A Maryland museum dedicated to Black history, housed in a historic church.

An abandoned church gets a second life as a massive beer hall and event space.

Meet some of the most prominent figures in Black history through life-sized wax models.

What was once a presidential estate is now an exotic menagerie and home to the Budweiser Clydesdales.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

When it comes to handsignals (and colonialism) rock always beats scissors.

Atop this media building, two hives containing more than 30,000 bees keep the surrounding area vibrant.

When it opened during the final years of the embargo, all the drinks and cigars were free.

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

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

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

The rogue roots are gradually consuming some of the historic marble grave markers.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The first presidential bomb shelter was located in an old vault under the Treasury, connected to the White House via tunnel.