What was once believed to be a church floor turned out to be the artwork of geology.

Where commuters walk through remnants of an ancient Greek necropolis.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

An ancient octagonal weather station named for the eight Greek gods of wind.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

A beautiful geyser under environmental threat.

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

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This stunning concert hall has become a symbol of Iceland's national recovery.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The last Viking king of Denmark is buried inside the crypt of this cathedral.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Generations have refused to move this doll from its dusty resting place to preserve a castle from a watery fate.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Raging waters have created a strange geological site that looks like something off of a progressive rock album cover.

The oldest (maybe) swimming pool in Iceland is a stunning oasis built into the side of a lush hill.

Along this wire fence, travelers have been leaving a particular memento since 2012.

A modern Nordic Pompeii on the Icelandic island of Heimaey.