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

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

This former Imperial summer home was the venue for a royal slap that once echoed 'round the world.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

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.

The ancient latrines of the Greeks, in all their public glory.

Ancient serpentine sacrifice holder that has stood the test of time.

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

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

Seven early Christians were sealed into a cave where legend has it they slept unharmed for centuries.

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

Over the centuries, this island paradise has done it all, from providing monks with ecclesiastical respite to sheltering an exiled Leon Trotsky.

Large miniature theme park with 100-plus models.

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

The best-preserved ancient theater in the world.

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

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

Roman ruins, natural methane fires and a lovely beach.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

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

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

Once described as the "Eagle's Nest," this ruined ancient city rests on a remote mountaintop.