A nostalgic bibliographic gem.

The national park was once a plantation estate.

The hidden offices underneath Memorial Bridge have been locked up since 1976.

A brass plaque dedicated to a convicted cannibal hangs in the National Press Club, and that's not even the craziest part of the story.

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

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

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

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

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

The house where John Wilkes Booth conspired with his co-conspirators.

This unassuming passageway played a key role in one of the most important events in U.S. history.

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

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

An overlooked tribute to one of the most important peace deals in American history.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

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

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

A much-maligned monument to teetotalism.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

The National Park Service’s best-kept secret with views that rival any in D.C.

A line of blue paint marks the route of the inaugural parade.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

Beneath unsuspecting visitors feet, a capsule containing pieces of America’s civil rights history.

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