This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

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 famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

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

The oldest continuously operating fish market in the United States.

A rotating cast of guys and dolls in front of a Washington, D.C. building.

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

The national park was once a plantation estate.

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

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."

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

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

A derelict bit of transportation infrastructure hidden in the woods.

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

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

A historic neighborhood church is reborn as a psychedelic arts collective.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

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.