 Mostly megalithic, the earliest instances date to within a few centuries of each other, yet show a wide diversity of form and purpose.Tombs in the Iberian peninsula have been dated through thermoluminescence to c. 4510 BCE, and some burials at the Carnac stones in Brittany also date back to the fifth millennium BCE.The commemorative value of such burial sites are indicated by the fact that, at some stage, they became elevated, and that the constructs, almost from the earliest, sought to be monumental.