There were three main building phases, each between about 3100 BC and 1950 BC. The first circle, ~3000 BC, was made of timber. The post holes for the timber have been found. Around 2600 BC, the builders gave up timber in favour of stone. Most of the construction took place between 2640 and 2480 BC. Scientists have discovered that the Stonehenge builders originated from modern day Turkey from DNA analysis.