A marvel of Byzantine engineering under the streets of Istanbul.

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

A deadly ancient portal to the underworld.

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

This hunter-gatherer architecture is believed to be the oldest religious complex known.

A sacred lake with thousands of sacred carp and a biblical history.

Mausoleum and Holy Seat of Antiochus I of Commagene.

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

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

Where commuters walk through remnants of an ancient Greek necropolis.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Large collection from the 3rd millennium BCE.

The hallucinogenic center of the ancient world.

This legendary city has been a tourist attraction for centuries.

According to myth, Zeus himself was hidden in this cave to escape being eaten by his dad.

Replicas of Apollo's leonine stone guard cats still line a sacred row in Greece.