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

A submerged archeological park still holds the wonders of a Roman Sodom.

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

An open-air museum in a mountain valley features works designed to blend in with—and disintegrate back into—their natural surroundings.

Geothermal waterfalls in Tuscany.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

An eccentric home in Sicily turns heads on a regular basis.

Thousands of well-dressed mummies below a monastery.

An ancient monastery, a locked room, and a mysterious book heist.

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

Notorious artist squat renovated into legal studios.

According to the locals, the sands of this secluded Norway beach are infused with gemstone particles.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

A floating underwater hotel, created by a Swedish artist.

Colorful and chaotic stacked hotel in North Holland.

A maze of crosses marks the jumbled divide between the Netherlands and Belgium.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

This amended headstone marks the grave of a participant in one of the most successful military deceptions of all time.

This small chapel is built of human bones and decorated with a golden skeleton.

A curious art park at the geographic center of Europe is home to 3,000 television sets and other wonders.

This wooden hotel is a temple to German sustainability and forest conservation.