The heads and relics of 179 monks slaughtered by pirates are on display within this Ceonobic Monastery.

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

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.

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.

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

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

The ruined doorway is a portal to the building's turbulent and torturous past.

After a catastrophic forest fire, a Greek artist transformed scorched tree trunks outside an old sanatorium into this haunting sculpture garden.

The abandoned summer estate of the former Greek Royal Family.

Τhis feline monument commemorates fallen soldiers on a field that saw many, many battles.

The hallucinogenic center of the ancient world.

Dedicated to the god Dionysus, this theatre was used for both musical and theatrical performances.

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

Legends hold that these unusual rock formations were once a bridal party, or perhaps a group of hunters.

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

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

These cascading falls resonate throughout the Bulgarian forest.

A massive cave once a secret military base is now home to thousands of bats.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

A spitting ode to a German serial killer.

A stunning gilt bronze relief denounced by Hitler as "degenerate art"—even though it was dedicated to the Nazi leader.

One room inside this building mesmerizes all with its parabolic dome.