These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

At this faithfully preserved medina off the Moroccan tourist circuit you can walk through six centuries of history in one day.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Double spiral staircases are not unheard of, but they are very rare.

Op-art architecture designed for happiness.

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

A little sculpture with a large wardrobe.

Theme park featuring miniature replicas of European monuments.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

Climb inside an iron crystal magnified 165 billion times its normal size.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This small chapel is built of human bones and decorated with a golden skeleton.

The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

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

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

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

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

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.