This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

One of the most spectacular 18th-century bridges in Scotland.

A forgotten "city of water" underneath the famous Trevi district.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

One of seven Jewish catacombs in Rome and one of only two open to the public.

The underground sanctuary of a mysterious ancient cult.

Architectureal fantasy quarter of Rome.

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

Drink wine handed out through a window as part of an age-old tradition.

The oldest operating pharmacy in the world features 800-year-old recipes.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

David Sedaris called it "The greatest shop in the world."

The remains of an ancient Roman city are hidden underneath Bologna's beautiful public library.

A small and surprising passageway in Saint Petersburg devoted to the Beatles.

A standing relief of a Norman knight whose posture marks him as a Crusader.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

Ruins battered by centuries of war and disaster offer a wondrous glimpse of medieval Ireland.

The ruins of an 800-year-old monastery boasts the tallest round tower in Ireland.

After being destroyed by IRA sympathizers, the ruins of this stately Irish manor have sat vacant for decades.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

While only two of the ancient buildings at this site are actually churches this was one of the earliest Irish pilgrimage sites ever.

A sacred well steeped in Pagan roots on the West Coast of Ireland.

An ancient neolithic tomb that only sees the sun twice a year.