A dark, narrow tunnel that leads to a charming lake and waterfall.

These ruins in Volvi were once at the intersection of the Eastern and Western Worlds.

Ruins of a 13th-century fortress perched above a breathtaking Mediterranean bay.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

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

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

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

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

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

An often overlooked ancient site in downtown Athens with substantial history (and nature).

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

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

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

The ghost town where the villagers refuse to leave.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This remarkable cave was discovered after a shepherd watched bees enter and exit through a small fissure.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.

Cave on extinct volcano, once home to famous mathematician Pythagoras.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

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

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

Hideout of thieves, monks, and goat-footed gods.

This Turkish cave boasts some rather bizarre associations with the King of Mount Olympus.