20 years ago today the Berlin Wall came down. Three authors of books on the fall of communism and its repercussions mark the occasion. Plus, 2009 is also the 10th anniversary of Radio Rookies, the WNYC program that lets teenagers tell their own stories on the air. Three past and current “rookies” talk about program and how it affected their lives. And, E.D. Hirsch argues for public schools and a core curriculum.