Stonehenge is not a single act of construction but a process that ran for at least fifteen hundred years. Around 3000 BCE the site was enclosed by a circular ditch and bank and seeded with timber posts and cremated human remains. Its stone phase began between 2900 and 2500 BCE: roughly eighty "bluestones" — some of them two-tonne dolerites — were brought from the Preseli Hills of Wales, more than 250 kilometres away. That transport alone outlines the coordination capacity of Neolithic Britain.

The silhouette the world recognises emerged around 2500 BCE, when massive sarsen blocks were hauled from the nearby Marlborough Downs and raised on site. Individual sarsens weighed up to twenty-five tonnes; lintels were placed across them to form a closed ring. The lintels were locked horizontally with mortise-and-tenon joints and tongue-and-groove fittings — woodworking techniques translated into stone. In this sense Stonehenge is at once engineering and sculpture.

The visual composition is deliberate. The monument is aligned so that the sun rises over the Heel Stone on the summer solstice; the winter solstice sunset falls along the opposite axis. Recent excavations at nearby Durrington Walls have repositioned Stonehenge as the centre of a far larger ritual landscape rather than an isolated ring. Hundreds of cremation burials placed in and around the circle make clear that the site was also a major funerary monument.

We do not know whose monument it was, what their cosmology was, or what names they used — writing had not yet reached Britain. UNESCO inscribed Stonehenge, with the nearby Avebury complex, onto the World Heritage list in 1986.