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

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

A monumental underground karstic wonderland is also the water source for over a million citizens of Beirut.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A very classy 1920s-era bar right in Grand Central Station.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.

A student driver's nightmare.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

World's largest bell sits on the grounds of the Kremlin in Moscow.

Former headquarters of the KGB.

The yawning maw of this pagan visage is said to bite off the hands of liars.

2300-year-old Roman road connecting the empire.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

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

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

Op-art architecture designed for happiness.

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

The topiary maze at the Habsburg hunting lodge.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.