Volume and Variety of Big data [Stonebraker, 2012] are significant impediments for anyone who wants to quickly understand what information is inside a large-scale dataset. Such data is often informally referred to as ’dark’ due to the difficulties of understanding its contents. For example, there are millions of structured tables available on the Web, but finding a specific table or summarizing all Web tables to understand what information is available is infeasible or very difficult because of the scale involved. Here we present and demonstrate CognitiveDB, an intelligent cognitive data management system that can quickly summarize the contents of an unexplored large-scale structured dataset, visualize it for interactive navigation, understanding, and support intelligent query processing.