A new study claims to have pinpointed the places in Pembrokeshire's Preseli Hills where Stonehenge's bluestone rocks were quarried.
Tests appear to show the rocks are from Carn Goedog and Craig Rhos-y-felin. The quarries are around 140 miles from Stonehenge.
Researchers also investigated in which direction stone-dragging teams would have travelled. They suggest they went North. The study says there is a possibility that the stones were erected in a temporary monument close to the quarries, before completing their journey to Stonehenge.
The study is published in the journal Antiquity.