Stonehenge, that famous stone circle. It incorporates stone from up to 120 miles away – transported before the invention of the wheel, and carved and lifted into place – before metal tools were used. But what actually is a henge?

The ditch was the earliest phase of the site. It was then developed, over millenia, and finished about 1800BC, to align with various sunrises and sunsets at key times of year. Its purpose remains a mystery, its iconic status for millions of tourists and a few modern-day druids unquestionable.