A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

Medieval torture techniques with a modern conscience.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

Pilgrimage site for star-crossed lovers.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Architectural monsters are devouring this palace's every door and window.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

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

Thousands of well-dressed mummies below a monastery.

Pompeii's less famous neighbor is still revealing her secrets.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

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

One of the biggest markets in Asia, under one of the continent's largest domes.

5,000 skulls in memorial to those killed by the Khmer Rouge.

A battle between nature and architecture in the Cambodian jungle.

Legend has it a commoner volunteered to be buried alive in the foundation so that the great fortress could be built.

Nineteen ancient rock-cut Buddhist caves can be found on the outskirts of Mumbai.

The oldest still-inhabited hill fort in India looks like a magnificent golden sandcastle.

Fifteen Jodhpur queens left their handprints before going to their fiery death.

This stunning 15th-century royal hill fort preserves the age of chivalry in Rajasthan.

Temples adorned with intricate, erotic sculptures make up one of the "seven wonders" of India.

An extraordinary "City of Caves" carved from solid stone.