A completely underwater art museum sends a stark message about humans' impact on the environment.

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

The most alien-looking place on Earth.

The bizarre rocks of Đavolja Varoš are the result of natural erosion.

Through the colossal entrance to this cave you'll find limestone tubs and an underground waterfall.

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

Nine caves filled with recently-discovered archaeological finds under the houses and the streets of the most ancient district of an old town.

Breathtaking and huge 430 year old maps of Italy.

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

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Southern Italy's spinning top village.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Founded as a refugee camp, now a popular tourist spot.