An Art Nouveau gem hides beneath the layers of city grime obscuring this once-magnificent building.

A marvel of Byzantine engineering under the streets of Istanbul.

A colossal statue of a woman hugging a modern building.

A surreal statue honoring Prague's favorite literary son.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

What looks like a suicide in progress is actually a statue of Sigmund Freud.

The first museum in the world devoted to sexual gadgetry.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

The unusual sculptures are believed to be powerful political symbols.

Explore the five senses depicted on this protruding Gothic window.

The world's longest and deepest train tunnel.

A nearly 500-year-old sculpture depicts a man eating a sack of babies, and no one is sure why.

An abandoned shopping gallery built during Fascist Italy tucked in the center of Palermo.

Why a column on the entrance is inscribed with a verse from the Quran is one of Sicily's many mysteries.

This unique museum is home to over 5,000 puppets of all types.

This triumphal 16th-century arched gateway leads to the oldest street in Palermo.

This artist's home turned gallery/museum preserves the creator's love of "Eastern" influences.

Inside the small garden of two mid-century apartment buildings stands a centuries-old bell tower, separated from its original church and hidden from view.

An architectural oddity where the triglyphs of the courtyard of walls create an optical illusion.

A room filled with frescos that make it seem like the walls are crumbling down while giants die in despair.

A surrealist timepiece by the artist of melting clocks.

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

Two bronze wolves atop this large rock honor the "Wolves of Tuscany" brigade of World War I.