Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

Long-abandoned art nouveau baths beneath Milan's Piazza Oberdan.

This abandoned Brutalist treehouse is a hidden architectural relic.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

This real life asylum of horrors is now an abandoned ruin that hides the unbreakable code to one patient's insanity.

The Sighignola summit on the Swiss border offers views so breathtaking it's been named one of the most beautiful places in Italy.

This museum is rotten with a century of wax medical deformities.

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

A fairytale island floats in the middle of Italy's little-known Lake Orta.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This large, circular tomb is the final resting place of the first emperor of Rome.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

This magical-looking island is notorious for the misfortunes suffered by its owners.

The plague quarantine island home to the alleged "Vampire of Venice."

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

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