Marking the passage of time was important to many ancient cultures. For the people of Stonehenge who were farmers, growing crops and tending herds of animals, knowing when the seasons were changing was important. Winter might have been a time of fear as the days grew shorter and colder. People must have longed for the return of light and warmth. Marking this yearly cycle may have been one of the reasons that Neolithic people constructed Stonehenge – a monument aligned to the movements of the sun.

The stones were shaped and set up to frame at least two important events in the annual solar cycle – the midwinter sunset at the winter solstice and the midsummer sunrise at the summer solstice.

At the summer solstice, around 21 June, the sun rises behind the Heel Stone and its first rays shine into the heart of Stonehenge. Although the tallest trilithon at the monument is no longer standing, the sun would have set between the narrow gap of these uprights during the winter solstice.