A clone of a cloned tree that was so important it allegedly had its own guards.

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

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

The world's oldest soul food restaurant is also one of its best.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

Home to a vast and influential collection of Shakespeareana.

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

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

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

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

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

Home to items never before seen by the public.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

An overlooked memorial honoring the local Washington residents who died in World War I.

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

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

A computer bug so primitive it was an actual insect.

Daily lunch spot for many of Washington, D.C.'s cab drivers.

The world’s largest magazine collection was born from a single shelf in a teen’s bedroom.