Did you know that the Sahara Desert used to be green? Farouk El-Baz, the director for the Center of Remote Sensing at Boston University, explains how the Sahara's sandy dunes were formed. We caught up with El-Baz at the annual meeting of the American Association for the Advancement of Science in Boston.
Music by Knife Crazy. Interview by Shumin Ma and Ira Flatow. Produced by Flora Lichtman.