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

The atmospheric road was never meant to be so creepy.

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

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Macabre astrological automaton clock dating to the late 1400s.

Eighteen miniature death-scene dioramas.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A hand-built folk art installation covered with messages of God's love.

America's most famous piece of self-built architecture.

France's most famous cemetery, with some of its most curious tombs.

A layered tribute to the work of mosaicist Isaiah Zagar.

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

Abandoned railway line circling the city of Paris.

The world's largest collection of witchcraft regalia.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Staves, storm-calling, and of course, necropants.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The ghostly remains of an accidental sea.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Hidden beneath the streets of London is a secret subway that only carried mail.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.