This elaborate hole in the ground was built as a sacred site for an ancient civilization.

Stalactites and stalagmites in a beautifully lit cave.

A striped 12th-century basilica sits in the countryside of Sardinia.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

High in the clouds of San Marino sits an ancient tower with some curious prisoner graffiti.

This 2,000-year-old Doric bridge is still open to pedestrian traffic to this day.

The location where a famous medieval knight was murdered.

This Renaissance square was at the center of Leonardo da Vinci's map, the first ichnographic ever.

This castle was once the home of one of the most powerful women of the Renaissance.

Also known as "Hell Alley," this tiny street in Imola gained its name in a bloody episode in the 16th-century.

This uniquely designed bridge served as the city gate for Comacchio.

An unusual sculpture with a meaning shrouded in mystery.

The roof of this ancient mausoleum is made from a single Istrian stone weighing a massive 230 tons.

Psychoanalyst Carl Jung reported a paranormal experience after visiting this mosaic-lined Roman baptistry.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

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

One of the largest squares in Europe contains an entire artificial island.

The tomb of the mythological founder of Padua is not hidden in some obscure crypt, but stands right in the middle of the city square.

The incorrupt tongue of the patron saint of lost things is venerated in this basilica.

The oldest botanical garden in the world that technically isn't the oldest.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

An unusual double-stelae obelisk with ancient and mysterious origins.