In 2008, students in Tom Gillespie's geography class at the University of California at Los Angeles were floating ideas for class projects. One student wanted to calculate changes in the size of refugee camps in Sudan. Another figured he could gauge the effectiveness of the military surge in Iraq by looking at aerial images of Baghdad at night. To execute these projects, the students planned to employ the methodologies and systems Gillespie had been teaching them about, primarily geographic information systems (GIS), remote-sensing and GPS. These satellite-based tools made even the most challenging undertaking seem possible, so it wasn't a complete surprise when someone (Gillespie can't recall just who) posed the question: why not try to find Osama bin Laden? "There had been no scientific attempt to figure out where he was," Gillespie says. "So I told the students, 'Look, guys, if you take this seriously, I will.' "