This stately 19th century library pushed architectural boundaries at a time when the public library movement was just taking off.

Narrow gorges and deep pools created by long-ago glaciers.

One of the oldest log cabins in America is one of the last of its kind this historic Swedish dwelling remains a piece of living history.

Pennsylvania's highest point is spotted with boulders which were pushed to the surface by nothing but cold.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

Contrary to what one might expect, ice forms inside this small cavern during the summer and melts during the winter.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

Locals call this magical moss-covered walkway the "Emerald Path."

The only geyser in the state of Pennsylvania is caused by pressure from an abandoned coal mine outside of the ghost town Centralia.

This lush forest valley was once mined for lumber to the extent that it was once nicknamed "The Pennsylvania Desert."

The residents of the Neighborhood of Make-Believe live without much fanfare within the Pittsburgh Children's Museum.

This semi-spooky remnant of an abandoned hotel provides fantastic views.

The oldest farmer's market in America is so ancient it was approved by the King of England.

The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

This church in Pittsburgh is home to the largest collection of religious relics in North America.

In the bowels of a 19th-century brewery lurks a fine-dining restaurant offering an array of themed feasts.

This Old Testament garden features 100 plants from biblical times.

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

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

In which a local geological marvel becomes a quaint roadside attraction.

This eerily well-preserved coal town was saved from destruction by a Sean Connery movie.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.