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

A submerged archeological park still holds the wonders of a Roman Sodom.

The middle finger of modernity.

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

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The underground sanctuary of a mysterious ancient cult.

The yawning maw of this pagan visage is said to bite off the hands of liars.

An alchemist's "magic door" stands in the middle of a Roman park.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

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

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Grave of the man allegedly responsible for a series of infamous murders in Boston in the 1960s.

Ice cream stand, snack bar, and time capsule of milk conveyance.

Dim sum, served in a grand old theater.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

The massive machine creates cracking displays of indoor lightning.

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

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

Three prestigious academic collections come together to create a world-class natural history museum.

"the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well . . . The pure Walden water is mingled with the sacred water of the Ganges."

A hidden gem, named after a San Franciscan icon, offers spectacular views of the Pacific Ocean.