Decades before the scandal, this staircase on the river was a literal "water gate."

A much-maligned monument to teetotalism.

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

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

Home to items never before seen by the public.

Bar full of oddities, specimens, artifacts and homages to the great dime museums of the past.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

This grand gothic brewery has been pumping out suds for over a hundred years.

Largest Roman Catholic church in North America.

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

Art deco landmark on the outskirts of Washington, D.C.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

This grave marks the passing of a historic Jane Doe whose identity remains a mystery to this day.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

A Beaux-Arts triumph set to become Ford's innovation campus

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

Sail through this subterranean show cave that is home to a legend that would go on to name nearly everything around it.