This once architecturally advanced housing complex is now a haven for squatters that still bears the scars of war.

The oldest standing Byzantine church in Athens is tucked within a monastery in the middle of an upscale shopping district.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

The only ancient site that remains on the south bank of the sacred Ilissos river.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

A Byzantine church containing the holy remnants of three saints sits atop the site of an ancient temple.

Where commuters walk through remnants of an ancient Greek necropolis.

These ancient ruins hide in plain sight next to a dessert shop.

This Ottoman-era church is hidden amid a busy tourist area.

A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Underneath one of the region's most historic roads lies the home of Plato's successor.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

Legend says this sacred tree was a gift from goddess Athena.

An ancient octagonal weather station named for the eight Greek gods of wind.

Legend says it was constructed with the destroyed pillar of an ancient Greek Temple.

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

A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

A Byzantine-era church hidden in a wooded area below the Acropolis.

A unique housing complex born from the aftermath of the Greek Civil War.

Elaborate stone houses constructed from the ruins of war.

The ruins of this ancient fortification wall sit in the middle of a quiet, residential intersection.

This graffitied 19th-century building was a prototype of European industrial architecture.

The ruins of this monumental city founded by the first Roman Emperor are strangely overlooked by most travelers.