Stonehenge's massive bluestones were transported over 240 kilometers from Wales without modern machinery.

Archaeologists have identified the specific source of Stonehenge's smaller bluestones as the Preseli Hills in Pembrokeshire, Wales. Research published in 2015 by University College London (UCL) pinpointed two specific quarries: Carn Goedog and Craig Rhos-y-felin. These sites contain naturally fractured volcanic rocks that prehistoric workers could detach using wooden wedges and water.The transport of these 2-tonne to 4-tonne stones occurred around 2500 BCE during the Neolithic period. While the larger sarsen stones came from just 24 kilometres away, the bluestones traveled between 225 and 290 kilometres. Experts believe the builders used a combination of overland hauling on timber sledges and water transport via the Bristol Channel and local rivers. This theory is supported by the discovery of ancient trackways and physical evidence of tool marks on the stones.In 2019, further excavations at the Waun Mawn site in Wales suggested that Stonehenge might have originally been constructed there before being dismantled and relocated to Wiltshire. This "recycled monument" theory explains the extraordinary distance these stones were moved. The logistical effort required hundreds of people working in coordinated shifts over several generations, making it one of the most significant examples of long-distance transport in the ancient world.