One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

Dim sum, served in a grand old theater.

Two thousand artifacts from around the world collected by one woman who loved to travel.

A beautiful Victorian-era cemetery, complete with a miniature village.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

The early American colonists were such ferocious drinkers the law actually required every town to have a tavern.

This tiny home built on revenge appears to be scarcely wider than a Volkswagen.

This popular bar has been blurring the line between normal and edgy for more than 75 years.

A museum dedicated to the history and exploration of both popular music and science fiction.

A 100-year-old purveyor of curiosities, curios, and kitsch featuring mummies, shrunken heads, and a Fiji Mermaid.

A promising candidate for the lost rock laid by George Washington was unearthed, but the hunt is still on.

A small token of gratitude from freezing cold journalists who were given a warm haven while covering JFK's inauguration.

Home to a vast and influential collection of Shakespeareana.

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

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

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

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

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

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The national park was once a plantation estate.

There's a crumbling old mansion inside the Smithsonian National Zoo.

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