Animations and diagrams can provide a rough guide to continental movements over time. But for a more precise picture, head for the Plate Tectonic Reconstruction Service from the Ocean Drilling Stratigraphic Network, a consortium sponsored by two German universities. The calculator determines continental locations at any time in the last 150 million years. The basic mapper plots plate positions at a specific time, and the advanced mapper lets you enter the coordinates of a modern site and find its location at different points in the past. Forwardthinking users can even project future plate movements.