The Public Broadcasting System consistently produces the finest programming on all of television. And, to this day, NOVA is consistently the finest science program ever to grace the tube. So it is with sober confidence that I can recommend this evening's installment: "Why the Towers Fell," which, of course, is a serious examination of what is now known about the World Trade Center disaster. Rest assured that because it is NOVA the program will be in-depth, probing, and non-sensationalistic. Check your local listings, as this strikes me as don't-miss programming.