An Australian lake whose pink hue defies scientific explanation.

Australian Lake set aglow by Noctiluca Scintillans.

Once the path of a railway tunnel, now home to thousands of glowing insects.

A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

An abandoned beach resort in Normandy reclaimed by artists.

Open since 1977, this small museum is filled with a lifetime of finds from a tireless traveler and collector.

A 15th-century Corsican chapel that possesses a rare Catholic monument: a "Scala Santa," or "Holy Stairs."

A young Gustave Eiffel assisted in the construction of this skinny metal observation tower.

From Carthage's Hannibal to riders of the Tour de France, many have crossed this scenic route through the Alps.

The ruins of a military fortification sit atop this mountain.

This imposing castle has stood for nearly a thousand years.

This massive and eclectic collection is filled with thousands of sculptures, masks, and assemblages.

This renovated Art Nouveau bathroom from 1905 is worth the price of admission.

This stunningly massive housing complex is a go-to filming location for dystopian sci-fi cinema.

An unusual, funny and fantastic open air museum.

These ramparts, once lined with towers, were constructed in defense of Beaune.

Erosion left these fascinating granite formations strewn across fields and mountains in Burgundy.

A breathtakingly steep set of stairs is carved directly into the face of the sea cliffs of Bonifacio.

After immigrating to Paris in the 1970s, two brothers from Laos built a grocery store empire.

Former bridge turned into an observation tower.

Once known as one of the finest tourist railways in Europe.

A bridge that dates back to the 12th century is said to have made the devil very angry.

This medieval chapel is now a shrine to the region's favorite sport.