During World War II, this rice mill became a Nazi concentration camp.

The smaller of the three towers of San Marino is a former prison inaccessible from the ground level.

High in the clouds of San Marino sits an ancient tower with some curious prisoner graffiti.

This exceptionally well-preserved ancient marvel also houses a small museum dedicated to Jordanian folk tradition.

An ancient capital city that dates back 3,000 years and harbors many surprises.

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

This crumbling medieval basilica once attracted pilgrims by the thousands to collect a miraculous dust that formed above the saint's tomb.

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.

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

A charming beach town in Turkey captures all the colors of the rainbow.

Standing proud atop a Turkish bluff, this Ottoman palace has retained its grandeur despite being abandoned for centuries.

Ottoman-era houses lovingly preserved.

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

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

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

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

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.

This famous city eluded concrete detection until the early 2000's.

Roman ruins top white travertine terraces formed by ancient hot springs.

A marvel of Byzantine engineering under the streets of Istanbul.

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

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.