This bridge was constructed from the rubble of the infamous Bastille.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

The location where the American Revolution ended.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

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

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

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

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

D.C. once had its own tiny rival to the New York Stock Exchange.

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

This nine-story building is the oldest standing skyscraper in D.C.

Once home to the largest photo service in the United States.

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

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.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

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.

Go take a picture with the inventor of the daguerreotype photographic process.

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

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

This statue of the "father of television" stands prominently in the United States Capitol.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.