The largest wine cellar in the world is a 150-mile network of underground caves near the capital of Moldova.

This subterranean necropolis holds three floors of antler-dug grave caves.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

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

Go inside to really appreciate this 500-year-old technological masterpiece.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

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

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

Venice's "Island of the Mad."

As can be expected from a centuries-old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

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

Rome’s legendary peephole vista is also a former Crusader stronghold.

Architectureal fantasy quarter of Rome.

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

Puffin enthusiasts flock to Europe's largest seabird cliff, which over one million birds call home.

Travel deep inside of Europe's second largest glacier in the world's largest man-made ice cave.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

Every summer local children form "pysja patrols" to save young birds that have wandered from their nests.

Learn about Iceland's hidden folk at this school dedicated to the study of elves.

This elegant arc of a waterfall marks a religious turning point.

The most powerful waterfall in all of Europe.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.