The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

The old church, buried by the 1784 Mount Vesuvius eruption, is a remarkably well-preserved place where people now pray for the souls of the dead.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

Thousands of well-dressed mummies below a monastery.

The walls and streets of the ancient city are peppered with penises.

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

This seaside Italian village doesn't just look Escher-esque, it actually inspired the mind-bending artist.

An abandoned quarry hides an open-air gallery of huge sculptures, some made from the rubble of 9/11.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

Ride a boat through this magnificent underground world, which now doubles as a theater.

An Italian hillside ghost town.

Though an earthquake destroyed this village in 1980, one former resident still walks its streets every day.

A mountain cave is the site of archaeological findings and Paleolithic rock art.

Three-story slide through the New Museum.

Tucked in the back of this amazing antique store is an important piece of medical history.

This impressive scene portrays the elusive forest giraffe of Central Africa.

Even for Egyptian royalty, the afterlife was bring-your-own-beef.

Outstanding taxidermy dioramas showcase the grandeur of the continent's wildlife with spooky realism.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

Captain America, Sub-Mariner, and the Human Torch were all born in this art deco Manhattan masterpiece.

This exemplar of modernist architecture is meant to captivate and inspire students of the Cooper Union.

Where now stands a 42-story condominium tower of marble, glass and steel was once the central market of New York’s slave trade.