A beautiful but toxic fountain of mercury.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

The "Little Ones," show Portugal in full miniature splendor.

His music once banned in Communist Cuba, John Lennon is now immortalized in bronze by Castro, who considers Lennon a "fellow dreamer."

The largest of London's subterranean rivers and once a mad, bad center of London life.

Ancient man-made caves underneath small town Belgium.

A circus legend leaves an unexpected endowment.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

Arrr! The most authentic collection of pirate artifacts in the world... matey.

Abandoned railroad tunnel is home to a colony of three million Mexican free-tail bats.

A Hawaiian stairway to heaven—that you can't climb.

Suburban observatory was personal lab of the father of modern astrophysics.

Iconic Los Angeles residence famous for its 19 statues of Michelangelo's David.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

Physicist’s epitaph provides final confirmation to a career of turmoil.

The ghostly remains of an accidental sea.

What happens when a sculptor has to find a way around a 100-year-old copyright.

Vaucanson's most famous automaton, brought back to life.

See the computer’s history revealed over the course of 20,000 years.

A comprehensive collection of Pez dispensers.

Started nearly 100 years ago, this science experiment just keeps on going, ever so slowly.

At just six feet two inches deep, it is said by Guiness and Ripley to be the world’s narrowest freestanding office building.

Ruins of the Crusaders' headquarters.