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

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

A computer bug so primitive it was an actual insect.

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.

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

Largest Roman Catholic church in North America.

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

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

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

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

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

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

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

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

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

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

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

The United States Capitol's former columns still stand.

2300-year-old Roman road connecting the empire.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Physicist’s epitaph provides final confirmation to a career of turmoil.

A massive mammoth bone has been on display inside this church since the 18th century.

A tree planted by Marie Curie is treasured by the Radium institute that she set up.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.