An Earth Magnetic Anomaly Grid (EMAG2) compiled from satellite, ship, and airborne magnetic measurements during a 2-year international collaborative effort was released in February 2009. Magnetic anomaly maps provide insights into the subsurface structure and composition of the Earths crust. They are widely used in the geological sciences and in resource exploration. Furthermore, the global magnetic map is useful in science education to illustrate plate tectonics, crustal interaction with the deep mantle, and other aspects of Earth evolution. Distinct patterns and magnetic signatures on magnetic anomaly maps can be attributed to the formation (seafloor spreading) and destruction (subduction zones) of oceanic crust, the formation of continental crust by accretion of terranes to cratonic areas, and large-scale volcanism.