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

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

A museum dedicated to exhibiting remarkable outsider art.

The aggressively banal name of this underground fortress of bureaucracy does little to evoke its truly surreal existence.

The land is home to swimming ponies and a legendary 18th-century treasure.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Climb inside an iron crystal magnified 165 billion times its normal size.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

Macabre astrological automaton clock dating to the late 1400s.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

"I did this all while you were watching TV."

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

America's only nuclear missile silo open to the public.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

Concrete strongholds stand guard over the Golden Gate.

The magic's in the hole!

This playground sculpture of an icon from the past is dedicated to the children of the future.

A former gold rush boomtown has managed to stay in business for over 100 ramshackle years.

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

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.