Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

European castle ruins in an American state park are actually the product of death and grief.

Less a museum than a bizarre fantasy world created by artists and engineers.

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

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 derelict bit of transportation infrastructure hidden in the woods.

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

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

A wondrous old library overlooking the nation's capital.

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

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

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

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

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

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

Home to items never before seen by the public.

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

The United States Capitol's former columns still stand.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

The largest burial mound in the United States holds the remains of prehistoric West Virginians.

A historic coal mine that doubles as a museum and tourist attraction.

This abandoned school has had many lives since the early 1900s, and all of them doomed.

Take a steam-powered ride straight out of the past on this Appalachian rail line.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.