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

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

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

The only Roman honorific column in Istanbul.

Taking the subway here means doing so over a bridge located in the middle of an estuary.

One of the newest mosques in a city filled with thousands.

A surprising and unconventional mosque hidden in the subsoil of Istanbul.

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

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

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

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.

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

A tiny park in the middle of some big power politics.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

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

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

A fountain standing as a testament to a doomed alliance.

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

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

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

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

A marvel of Byzantine engineering under the streets of Istanbul.

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

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