This claimant to the title of "smallest church in the 48 states" doubles as an equally tiny, quasi-post office.

This massive airship factory is so large that it has its own indoor weather.

Memorials and tributes scattered across the university grounds remember a famous national tragedy of the Nixon era.

This university transit system is a 1970's vision of the future.

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

Beyond the usual stories that attend old prisons, this one has deep bloody undercurrents.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

The aggressively banal name of this underground fortress of bureaucracy does little to evoke its truly surreal existence.

Despite its lavish ornamentation, and wholesome lifestyle of its devotees, this mountain commune has faced its share of issues.

The universally beloved children's television figure is interred on a high hilltop in one of western Pennsylvania's oldest cemeteries.

House of vintage taxidermy and Steampunk sculptures in a quiet Pittsburgh neighborhood.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

This eccentric mansion museum holds a impressive collection of rare and automatic instruments.

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

Long hidden under grime, the politically radical murals of a little known Yugoslavian master are finally getting their due.

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

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

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

A super-sized promotional trick that is now a D.C. landmark.

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

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

The United States Capitol's former columns still stand.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

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