An ancient and majestic fortress that played an integral role in Portugal's road to independence.

A unique seaside cave where Aleister Crowley faked his own death.

The stunning interior of this Gothic church is covered in ornate gold details.

Houses are tucked between, on, and underneath giant boulders.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

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

This hauntingly beautiful cemetery outside a medieval citadel is full of winding paths and ivy-covered graves.

One of the oldest churches in Romania is believed to have been built on the site of a pagan temple.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

A small town Romanian cemetery filled with darkly humorous gravestones.

Science fiction's grandfather has a fittingly marvelous tomb.

A beautiful Victorian-era cemetery, complete with a miniature village.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

This massive library holds what was once the largest book collection in the world.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

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

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

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

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