He walks through the construction timeline of Stonehenge, noting that work began around 3,000 BC and continued for two thousand years. The megaliths fall into two categories: the massive sarsen stones, which are silcrete sourced from Westwoods near Marlborough about 25 kilometers north, and the smaller bluestones. The sarsens had to be quarried and then hauled across significant distance, a monumental undertaking that speaks to the level of organization and purpose behind the site. What drove these people to move stones of that size over such terrain? The effort alone suggests Stonehenge was far more than a casual monument. It was a project of profound importance, one that required sustained commitment across generations.