North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

These lush botanical gardens employ the most purrfect pest control force.

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

A glittering Thai Buddhist temple in suburban Pennsylvania.

A field of nothing but boulders which resembles a giant's gravel driveway.

A larger-than-life statue of America's favorite sundae marks the place it was invented.

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

Current docking place of the SS United States, the fastest transatlantic ocean liner.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

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

Erected in 1697 this Philadelphia bridge is the oldest surviving roadway bridge and perhaps the oldest stone bridge in the United States.

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

The pop art icon's gravesite is broadcast 24 hours a day on his museum's website.

This jail which was in service for over a century is now open for curious visitors.

This restaurant offers a side of antiques, curios, and a bathroom chock full of owls.

The home and studio of a visionary woodworker now stands as a museum and example of his artistic genius.

Once on display alongside a giant Gumby, it’s as tall as a nine-story building when fully extended.

This Pennsylvania cave holds evidence of the oldest known inhabitants of North America.

This secluded walking trail is a hidden gem of a Pittsburgh park.

Its vintage camera collection gives a snapshot of the past as viewed through a photographic lens.

This elaborate towering structure was once famed for its revolutionary height.

One man's real life disfigurement inspired a lasting local legend surrounding an eerie tunnel.

Board a mine car and descend the #190 slope 300 feet underground into the Clark Vein of coal.

Pennsylvanian mass grave and possibly mass murder.