The Pierre Plate Dolmen was built about 2600 BC. Dolmens are collective tombs that must also have played an important role in the identity and cohesion of the social group that built them (called the Treilles Group by archaeologists, after the name of a cave that it once occupied). These tomb builders were caving pioneers: they ventured into the depths of swallow holes to get water and clay. They were also innovators, producing very beautiful stone arrowheads shaped like fir trees and soon afterwards learning to fashion copper (arrowheads, daggers, axes).