Stonehenge was not built in a single moment but over roughly 1,500 years. In its first phase, around 3,000 BCE, it was a circular bank-and-ditch with timber posts. Some five hundred years later the great sarsen stones (each up to 25 tonnes) were dragged from about 30 km away, and the smaller bluestones from the Preseli Hills in Wales, some 240 km distant.

What astonishes most is the astronomical alignment: the principal axis points to sunrise at the summer solstice and sunset at the winter solstice. It is among the clearest evidence we have of how carefully prehistoric communities watched the sky.

Stonehenge's function was likely plural: ceremonial centre, burial complex, calendar, and possibly a place of healing. Excavations at nearby Durrington Walls show that thousands of people gathered seasonally during its construction — a scale of coordination without precedent at the time. The site was inscribed as a UNESCO World Heritage Site in 1986.