This freshwater spring fills with 10,000 gallons of water per minute.

The origin of the Nixon tapes is rooted in technological incompetence as much as secrecy.

Unique Michigan homes look like something out of Tolkien's "The Lord of the Rings."

It was once the base for a series of domestic terror attacks.

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

The watery grave of an impractical idea.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

The literary king of the Jazz Age was born in this lovely Minnesota home which still honors his legacy.

One of the coolest murals in Minneapolis.

An amazing collection of sculptures and art.

Fragments of architectural wonders from around the globe are embedded in the newspaper building's walls.

A display of magnificent stained glass windows is the first exhibit of its kind.

This $3 million model train takes you through Chicago, Seattle, and the thousands of miles in between.

Where experiments are conducted on all things wood.

Paranormal activity on the great lakes.

Statue dedicated to the star of an old television show.

Erotic art covers the walls of the largest ancient pleasure palace.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

An ancient Egyptian temple in the middle of Madrid, Spain.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

The famous winding walk at Chartres is surrounded in mystery and myth.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

The comedy and tragedy of Oscar Wilde is preserved in a Dublin park, captured in a sculpture of colorful stone.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.