Where America's first doomsday cult awaited the end of the world.

An exquisite tunnel of cascading flowers.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

Fragments of human bones are embedded in the walls of this quaint alley.

This deceptively salty lake looks like blushing pink lemonade.

The world's largest wooden structure.

A 500-year-old series of tunnels long believed to be folkloric was uncovered beneath the streets of Puebla.

A remote hilltop covered in giant monoliths haunts the Brittany countryside.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

A nearly 25-foot concrete sculpture of Sylvette, Picasso's muse.

A curious collection dedicated to human and animal anatomy and pathology.

A formerly glacier-tipped volcano that inspired none other than Jules Verne.

A winding, blood-red tunnel of hardened lava navigable by foot.

This magnificent stepwell is designed as an inverted temple and adorned with 1,500 sculptures.

A whimsical garden of outsider art in the Spanish countryside.

A fifth-century temple improbably built into the side of a cliff.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

A medieval military street hidden beneath a charming French fishing village.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

100-windowed castle turned art gallery, built by one dedicated mason.

A Spanish town built into the cliffs.