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

A favorite of Amelia Earhart, ranking among those rare bridges that can be crossed without changing sides of the river.

This beautiful stone arch bridge wasn't even expected to stand for one day, but people have been crossing it for centuries.

One of the last few period-correct, hand-operated canal locks in the country.

It marks the spooky spot where the bodies of two young boys were found in the 19th century.

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

The mortal remains of a Russian prince, priest and paranormal investigator who came to America in 1792.

Collection of trolley cars in the woods represent one man's attempt to preserve transportation history.

A well-preserved relic of the industrial age steel and iron works that dotted West Virginia.

A living maritime paradox still floats in the same lake where it was built and resurrected... or was it?

The ruined remains of a coal mining ghost town are hidden within the woods.

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

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

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

This historic furnace was once used to produce cannonballs during the Civil War.

A miniature golf course crafted inside the world's largest simulated cave.

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

This museum is dedicated to the first coast-to-coast highway.

This outdoor exhibit features a historic wooden dam once used to help boats navigate the Ohio River.

The crash of this great airship signaled the beginning of the end for dirigibles.

The only statue of its kind to commemorate Washington's beginnings as an officer of the British Colonial Militia.

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

For decades, it has disappeared and reappeared as water levels rise and fall.

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