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

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

A haunting tribute to pioneering photographer Clover Adams.

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

Largest Roman Catholic church in North America.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

The national park was once a plantation estate.

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

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

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

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

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

Fittingly, America's museum of architecture is itself a magnificently designed old building.

A painfully obvious spy house sits right across the street from the Russian Embassy.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Home to items never before seen by the public.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

The site of the climactic scene from the classic horror film is now a historic landmark.

The United States Capitol's former columns still stand.

America's first nuclear-powered merchant ship is now a time warp to the atomic age.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

Ship skeletons haunt Baltimore's waterways.