My World GIS is a geographic information system (GIS) designed for use in middle school through college classrooms. It has been developed by the GEODE Initiative at Northwestern University as part of a research program on the adaptation of scientific visualization and data analysis tools to support inquiry-based learning. My World gives learners access to geographic data about our world. It offers easy-to-use tools to perform investigation and analysis as they explore critical issues about the environment, geography, geology, demography, history, and much more. Data visualization is ideally suited for learners because it provides a powerful way to make visible the patterns and trends that lie hidden in complex data. My World provides a carefully selected subset of the features of a professional GIS environment. These features include multiple geographic projections, table and map views of data, distance-measurement tools, buffering and query operations, and customizable map display. They have been selected to provide the greatest value to students without overwhelming them with complexity. Additional features targeted specifically at educational users have been added, including functions that make it easy for teachers and curriculum developers to distribute data to students and to provide students with background information and instructions online.