If it is difficult for students to imagine life in ancient times, it is often harder for them to understand how archaeologists use fragments of evidence to reconstruct those remote images. In the average archaeology classroom, university students are told a story of the human past - a narrative that weaves together the names and dates of different sites and prehistoric cultures.

The best teachers illustrate this narrative well, with slides, videos, museum exhibits or artifact replicas. Some teachers explain case studies of important sites to give students an idea of how archaeologists work. But few students in any introductory archaeology or prehistory course get a realistic experience in the collaborative teamwork and interpretive debate which is so central to archaeological enquiry.

Prehistoric Puzzles is a a rich, interactive, problem-based web environment in which students can actively collaborate to explore and learn to interpret authentic data from real archaeological sites.

The Site of Nabta Playa, a Neolithic site in the Egyptian Western Desert, has the earliest example of a calendar circle in the world. The circle, which looks a little like a small Stonehenge, is more than 8000 years old.