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

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

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

1513 Turkish world map, full of European state secrets and snarky commentary.

A pair of connected skyscrapers form this symbolic gateway.

Opulence and fantasy collide in this royal chair which is supposedly made with unicorn horns.

Sky ships, planes, and portraits left as unique tokens of hope and thankfulness.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

This bridge was constructed from the rubble of the infamous Bastille.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

The world's only silo that was topped by two revolving restaurants has unfortunately been demolished.

Apartment complexes built into huge repurposed natural gas tanks.

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

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

A fake medieval village in the middle of Turin.

This insurance company building reminds customers that witches, bears, and gnomes are out there, best be insured.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.