Decades before the scandal, this staircase on the river was a literal "water gate."

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

It was once the base for a series of domestic terror attacks.

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

Seemingly unremarkable items like empty sushi trays, chef hats, and freshness stickers are being preserved so future generations can look back on this beloved cultural import.

A super-sized promotional trick that is now a D.C. landmark.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

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

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

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

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

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

A wondrous old library overlooking the nation's capital.

A historic neighborhood church is reborn as a psychedelic arts collective.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

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

A tiny piece of the Moon is embedded in this stained glass masterpiece.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

Home to items never before seen by the public.