A 140-year-old castle with underground caves hidden in San Francisco.

Pompeii's less famous neighbor is still revealing her secrets.

Every autumn, this hillside is ablaze with red summer cypress.

One person's lost luggage is another person's treasure.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

Famously misunderstood wonder of the ancient world

Two stunning 17th-century libraries and a cabinet of curiosities.

A fictional town that was briefly brought to life before fading once again out of existence.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

One of England's most famous churches hides a pair of little known architectural treasures.

Grotto replete with mystical designs laid out in glued shell mosaics.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

The fairy tale castle of the "fairy-tale king."

A crumbling hospital from the 1850s on Roosevelt Island.

The Art Deco Silver Screen.

Home to the Amorphophallus titanum "Corpse Flower," which is among the largest flowers in the world and also smells powerfully of rotting flesh when in bloom.

20,000 pieces in a Frank Gehry-designed building.

Secret hideaway for an alternative beach experience.

Hub of Scandinavian culture in a Minneapolis deli.

The “American Gothic" artist's largest works hang in an Iowa State University library.

The largest collection of historical roller skates in the world.

A lifetime's accumulation of bric-a-brac and kitsch.