Vast collections of video and audio recordings which have captured events of the last century remain a largely untapped resource of historical and scientific value. The Informedia Digital Video Library has pioneered techniques for automated video and audio indexing, navigation, visualization, search and retrieval and embedded them in a system for use in education and information mining. In recent work we introduce new paradigms for knowledge discovery by aggregating and integrating video content on-demand to enable summarization and visualization in response to queries in a useful broader context, starting with historic and geographic perspectives.