A shrine of fire worship built on top of a natural flame.

An unoccupied lighthouse encased in layers of ice from the waters of Lake Erie.

Lebanese castle built by one man, over a lifetime.

Renaissance villa and gardens complete with a tormented colossus.

Cavernous opening completely encased in Karst limestone.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Northern Ireland's Brobdingnagian stepping stones.

The lake that fills and empties itself at random.

This stately estate house features a tower covered in a bright, modern mural.

A 30-acre garden inspired by the principles of modern physics.

Legend says this cave housed a 16th-century cannibal and his family of 48.

A snake farm famous for its venemous varieties.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

A 18th century graveyard and its astonishing cortege of macabre iconography.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A spectacular cave and a beguiling lake.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

An underground city of salt.

The long, arduous journey of the stones of the Abbey of New Clairvaux.

Seaside ruins of a settlement that date back to the first century B.C.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.