Walk through the history of American pop culture.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

This free, take-a-book shop seems like a trick but isn't.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

These recently uncovered walls are all that's left of Washington, D.C's first defense contractor.

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

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

Largest Roman Catholic church in North America.

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

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

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

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

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

A derelict bit of transportation infrastructure hidden in the woods.

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

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

A wondrous old library overlooking the nation's capital.

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

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

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

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