Medical and zoological curiosities for sale.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

Medicinal spa created with the discharge from a geothermal energy plant.

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

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

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

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

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

A bizarre house filled with an astounding array of collections.

This weird abode has inspired everything from the "House On Haunted Hil" to a robot hunter's pad.

Left untouched since a double murder-suicide in the 1960s, Los Feliz murder mansion remains a neighborhood mystery.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

An emerald-green grotto just a short trip from Austin.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A snapshot of the city's fascinating voodoo culture.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

On the Oregon coast there is a natural hole that seems to be draining the sea.