The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Before founding the American Red Cross, Clara Barton had a tremendous humanitarian impact by locating thousands of missing soldiers.

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

Senators used to relax in the nearly forgotten marble tubs now hidden in the U.S. Capitol Building's basement.

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

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

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

Perhaps the most scandalous statue of America's first president.

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

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

The national park was once a plantation estate.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

The walls of the iconic dome are hollow and have a secret stairway.

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

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

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

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

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

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

The United States Capitol's former columns still stand.

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

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

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