The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

2300-year-old Roman road connecting the empire.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

The underground sanctuary of a mysterious ancient cult.

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

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

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

A legendary speakeasy bookstore returns from the brink.

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

More gold than anywhere else, ever.

Become a prohibition rebel.

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

A hands-on traveling collection of the innovative devices of yesteryear.

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

Architectureal fantasy quarter of Rome.

New York City's smallest piece of private property.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

Read a book next to a Midtown waterfall.

This little museum is built on a theater that was once a wildly elaborate speakeasy.