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

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A trash dump made beautiful by nature's power.

The ghostly remains of an accidental sea.

A snapshot of the city's fascinating voodoo culture.

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

A massive underwater sinkhole made famous by Jacques Cousteau.

A 16th-century horror show built in a lovely Italian garden.

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

Dramatic river bend surrounds a natural red-rocked pedestal.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

The legendary building that needed ghostly approval before being built.

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

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Most-visited and most-photographed slot canyon in the American Southwest.

An artsy hidden staircase leads to breathtaking views of San Francisco.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Rippling sand dunes frozen in the Arizona rock.

An exquisite tunnel of cascading flowers.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.