An acoustic anomaly with a mysterious cause.

This nearly abandoned town was once a thriving mining community until a series of fires.

The oldest remaining authentic Putt-Putt course that Donald Clayton created in Ohio.

The medieval legend behind this holy well was one of the inspirations behind "Alice's Adventures in Wonderland."

Anna Anderson spent most of her life claiming to be the lost Romanov child Anastasia.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A melancholy guardian doubles as a judicious godmother to this small town cemetery.

This sturdy, circular stronghold served as one of the forts that protected the Venetian Lagoon.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Passengers are not allowed to set foot outside this station, but you can still enjoy spectacular views of the sea from the platform.

In the 19th century, this pit housed a fully grown black bear for the entertainment of visitors. Today there is a sculpture in tribute to the poor creature.

Touching this little fossil embedded in the wall of a grand mosque-cathedral may make your wishes come true.

A discarded movie prop that was the original monolith for "2001: A Space Odyssey."

These three lighthouses played a fundamental role in the maritime life of Eastham.

The oldest (maybe) swimming pool in Iceland is a stunning oasis built into the side of a lush hill.

The oldest continuously-operating Chinese restaurant in the United States has been in business since 1911.

Chiseled out of a sandstone cliff, one farmer's unfinished art project lies in ruins.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

The last remaining predreadnought battleship in the world has been a museum for nearly a century.

Experience this Iron Age village the way that its original residents would have.

For decades, vendors have sold clothes once worn by American soldiers who stormed Italy in the 1940s.

The body of an unidentified woman, visible through a glass coffin, was discovered by accident.

The grotto where Saint Ignatius of Loyola lived as a hermit for nearly a year.

Climb to the top of its spiral spire for spectacular views of Copenhagen.