An 800-year-old island castle in Guernsey's main harbor.

An intricately decorated tiny place of worship.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

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

Where commuters walk through remnants of an ancient Greek necropolis.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

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

View the ancient remains of buildings and the ancient "River of Hades" before hopping on a train.