"The History Engine is an educational tool that gives students the opportunity to learn history by doing the work-researching, writing, and publishing-of a historian. The result is an ever-growing collection of historical articles or "episodes" that paints a wide-ranging portrait of life in the United States throughout its history and that is available to scholars, teachers, and the general public in our online database."
Via http://www.freetech4teachers.com/2012/04/history-engine-explore-stories-of.html