The half-mile long structure is so impressive, it even shows up on satellite images.

One of the foremost Sherlock Holmes collections is hidden away at a Toronto library.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

A lush green oasis in the middle of Chicago.

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

The astonishing collection of an infamous criminologist.

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

Crushed coral and crystals give the sand its signature coloration.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

This enchanting 600-year-old tree is so magical it inspired the beloved tale of Pinocchio.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

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

Thousands of well-dressed mummies below a monastery.

Geothermal waterfalls in Tuscany.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

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

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

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

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

Architectureal fantasy quarter of Rome.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.