No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.

This museum was invented in a novel before being made real by the author.

The most metal church of all time was built in record time because of an international, pious pissing contest.

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

Step back in time and witness the fall of Constantinople.

A sixth-century Byzantine cistern hidden below a modern carpet store.

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

This crucial gathering spot along the "hippie trail" still displays old notes between traveling beatniks and backpackers.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Turkish adventurer antiques in the heart of the Grand Bazaar.

Have tea in a cemetery with a dazzling view of Istanbul.

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

The ornate miniature mansions were built for Istanbul's feathered residents.

A marvel of Byzantine engineering under the streets of Istanbul.

This historic hotel preserves many treasures from its heyday hosting passengers on the Orient Express.

A notoriously corrupt Chief of Police's deteriorating Greek-themed playhouse.

Just across from the "Last Supper" painting is the famous painter's vineyard, a gift received for creating the masterpiece.

A Milanese café entirely designed by the American director Wes Anderson.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.

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

In one of the world's smallest countries, a royal's personal winery is open to the public.

A tiny rural community in Switzerland was home to one of history's most shocking murders, and led to the banning of Absinthe for nearly a century.

Spiral alpine structure provides an alternative experience of viewing the Matterhorn.