Odd outsider art installations surround a Gold Rush-era ghost town.

This abandoned prison castle has become an imposing gallery of graffiti art.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.

An ancient cemetery hides behind a line of disparate chapels.

Unbeknownst to many, an ancient burial mound hides in plain sight in Ueno Park.

A former millstone quarry in the Italian Alps is strewn with rocks bearing distinct round shapes.

A phantasmagoric tomb honors a Belgian artist-scientist's contributions to the world of spooky entertainment.

Like your grandma's attic—if your grandma were a little weirder, extremely well-traveled, and had a great eye for art.

The ruins of this once-grand mansion are linked to one of the country’s most popular clothing brands.

A network of ancient tunnels and vaulted chambers with mystical Buddhist reliefs, built for ascetic training.

The world's most comprehensive collection of Willard timepieces is a celebration of early American clockmaking.

Where a troll might repair your shoes in exchange for a bowl of porridge.

The spectacular geological formations make it one of the most impressive caves in Europe.

This prehistoric karst cave is situated near a working ranch and historic warm springs.

The mirrored section takes the shape of Hebrew characters when viewed from above.

This fortress-like monastery is covered with intricate frescoes.

An immense cave that has served as an outlaw's treasure trove, an underground dance hall, a nuclear fallout shelter, and much more.

This pond in Victoria Park is rumored to be bottomless, one of several legends that surround it.

An ancient stone structure that, according to legend, was built by witches.

A tree that defies gravity grows in an ancient ruin.

Besides being home to cave paintings and pre-Columbian Cuban archaeological remains, you get to take a boat through this stalactite and stalagmite covered cave.

Three tiny islands in a Portsmouth pond are at the center of disputed land claims from a number of competing micronations.

The remains of "the Pearl of Scotland" can be found inside this church.