A trough of 700 strange bronze faces runs through a narrow alley in Ljubljana's old town.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

Walk 2,300 feet above the ground on the "Troll's Tongue."

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

A quirky bookstore hidden beneath a sea of whitewashed Greek villas.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

Legend says this sacred tree was a gift from goddess Athena.

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

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

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

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

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

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

Baroque celebration of the end of the Great Plague of Vienna.

Op-art architecture designed for happiness.

The beautiful baroque library of the Hapsburg empire.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

The history and future of cannabis.

This 22-floor tower's Skydeck offers panoramic views of Amsterdam.