A long abandoned hospital building on the outskirts of NYC.

A collection of full-size movie monsters opened to the public.

Lost subway station nestled beneath Toronto's busy commuter line.

This chilly Canadian hotel has a four-month lifespan due to the unusual material it's made of.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

The most alien-looking place on Earth.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

Centuries-old bridges grown from tangled roots.

The sign at the garden gate reads: "These Plants Can Kill."

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ethereal glowing blue ocean cave in Croatia.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

Bioluminescent firefly squid light up this Japanese fishing port.

The world's brightest bioluminescent bay.

Vortex-shaped aquarium hosts Europe's largest school of piranhas and other ocean creatures.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.

World's largest collection of serial killer artwork and other macabre exhibits.

This deceptively salty lake looks like blushing pink lemonade.

Submerged trees jut ghost-like out of an idyllic turquoise mountain lake.

Natural time capsule containing an alien ecosystem.

A seemingly endless landscape of pure salt stretches far across Bolivia.

A gargantuan crystal kingdom.

An isolated dive site teeming with cnidarians.

An explosion of natural color known as "the river that ran away from paradise."