Mysterious rocks that ring musically when struck.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

An ancient knight and a symbol of the city's freedom.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

Gargoyle head that brings good luck.

A rock maze opens up to a panoramic viewpoint at an abandoned mine full of ghost stories.

This historic Pittsburgh tennis complex is a rare example of natural red clay courts.

The site of America's first commercial oil well essentially disappeared after the town went bust.

A hidden piece of Altoona's railroad history in a long-forgotten abandoned town.

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

Dozens upon dozens of boulders engraved with scripture tell the story of one man's troubled life.

Each step is a mere 4 inches tall, said to be measured by the stride of a woman wearing a hobble skirt.

A museum commemorating the Donora Smog, which killed 20 people in October 1948 and sparked national outrage over air pollution.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

The site of the little-known Pennsylvania battle that sparked the Seven Years' War.

A preserved 18th century homestead in Western Pennsylvania marks the spot where the Whiskey Rebellion began.

Pittsburgh's literal underground railroad.

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

It would take 35 firetrucks to fill this enormous glacial pothole.

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

A macabre farm reserved part of its 222-acres for dead bodies, all in the name of science.