The first botanical garden, a feather in the cap of the Grand Duke of Tuscany.

This winding road through an Italian canyon may be the most scenic drive in the world.

Geothermal waterfalls in Tuscany.

This 16th-century monastery has been turned into a surrealist architecture compound.

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

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

Balconies that have a most unusual accent.

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

This collection of French root art looks like an indoor fairy wonderland.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

A Gothic cathedral created from volcanic rocks.

The largest underground church in Europe.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

This series of Scottish caves has no clear purpose other than baffling historians.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

A gallery specifically dedicated to the botanical illustrations of a remarkable traveling lady.