An underground network of massive stone arches and their skylit vaults support ruins of portico structures above.

These ruins once flourished as the capital of the Lydian kingdom, often credited with the invention of metal coinage.

A deadly ancient portal to the underworld.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Ottoman-era houses lovingly preserved.

The only residents of this abandoned housing development full of identical castles are stray cats and dogs.

Step back in time and witness the fall of Constantinople.

Climb a set of vertiginous stone steps to the top of this impressive ancient edifice.

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

This eatery re-creates dishes from the Ottoman Empire so you can dine like a sultan.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

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

A section of the long chain that blocked enemy ships from entering Constantinople.

Quite possibly the oldest love poem known to humankind.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

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

Legend says if you stick your thumb in the hole and it gets wet your wish will be granted.

A serpentine highway twists and turns over the treacherous Norwegian Sea.

These medieval tunnels provided water to the city above through centuries of civil war and plague.

A castle in the Scottish Highlands has been continuously inhabited since the 1300s.

On this stunning Scottish island, you can walk in the footsteps of dinosaurs.

The abandoned railway bridge stands hidden in the farmland of rural Cumbria.

A beautiful medieval bridge allegedly constructed by the Devil.