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

These decaying bridges 1,000 feet high are a reminder of the skill it took to cross the Colorado Rockies by rail.

The wreckage of a World War II bomber is hidden high in the Colorado wilderness.

Community owned and operated, this property is home to a diverse set of nudists.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

The haunted reputation of these abandoned Colorado train tunnels is probably not helped by the terrifying spiked fence.

Silver in the hills led to the speedy creation of this boom town and a lack of it saw the town abandoned nearly as quickly.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

Once the largest windmill outside of Holland, with enormous 114 foot sails.

A 300-ship graveyard, with a few still visible at low tide.

A man-made island in scenic San Francisco Bay.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

The remains of a ruined mansion memorialize the 1906 earthquake.

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

San Francisco's first World's Fair, dedicated to the wonders of California.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

This turn of the century masterpiece has a mysterious goaty interloper.

San Francisco's newly reopened hands-on science museum.

A psychedelic labyrinth on the San Francisco bay.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

A library built during San Francisco's pioneer times is a student's retreat, bibliophile's sanctuary, and chess player's delight.

With the touch of a button, you can read a randomly selected short story.

A collection of 20th-century automata, penny arcade games, and musical contraptions.