Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

This World War I fortress is the perfect place to catch a Montenegrin sunset.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

The only known mosaic depicting the Greek god of sleep, Hypnos.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A mysterious ancient elephant said to possess magic powers is now the symbol of a Sicilian city.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

Fortified medieval tower house with lovely roof garden.

A local student's chance encounter with Keith Haring led to the creation of one of Europe's largest murals.

This historic streetcar system has been running since the 19th-century.

As the highest point in the Mid-Atlantic range this stratovolcano offers spectacular views.

Perhaps the most spectacular grotto along the Algarve coastline.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This giant sculpture made of trash is a critique of society's wastefulness.

Elaborate tile work in this railway station tells the story of Portugal.

A hidden three-foot-wide house separates these two regal churches.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.