Archaeologists have just discovered an inextricable network of galleries, shafts and chambers.

About 5 kilometers of subterranean conduits dug in the marble and the limeschists of Attica have been explored and surveyed. These lead to labyrinths of complex mining works the height of which often does not exceed 30 cm. It constitutes at present the widest underground network explored in this part of the Aegean world.

Source: The Archaeology News Network: An exceptional discovery at Thorikos, Greece