National Geographic hosts the Atlas of the Human Journey, one of the products of the Genographic Project. “The National Geographic Society, IBM, geneticist Spencer Wells, and the Waitt Family Foundation have launched the Genographic Project, a five-year effort to understand the human journey—where we came from and how we got to where we live today.” The Atlas of the Human Journey shows the world through various stages of pre-history - from 200,000 BC to 10,000 BC. Ice cover, human migration routes and selected key sites are displayed. The sites are hotlinked to other pages that display more detailed information and maps. Requires the Flash plug-in. More details about the project here and here.