Architectureal fantasy quarter of Rome.

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

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

The beautiful baroque library of the Hapsburg empire.

Macabre astrological automaton clock dating to the late 1400s.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Two stunning 17th-century libraries and a cabinet of curiosities.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Real bones which are said to have belonged to a Polish dragon.

An underground city of salt.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

A miraculous three-handed portrait of a saint can be found inside this church.

Plaques celebrating Lithuanian writers freckle a wall of this picture-perfect path.

A 300-kilogram egg sculpture that embodied a neighborhood revival.

A century-old prison in the heart of Vilnius is now a lively bar, dance club, and artist residency.

These traffic lights celebrate the 100 year anniversary of the women's suffrage movement in Lithuania.

An abandoned masterpiece of Soviet Brutalist architecture.

Over time, this castle grew to encompass the entire island.

Travelers who fall victim to this mermaid's charms are destined to stay in Užupis forever.

This micro-nation may be some sort of prank, but its constitution sure seems official.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

"There's nothing there," and other lies the KGB told us.