WWLTV aired a special called Eye on Hurricanes. You can watch it online at this link. It is slpit in 4 parts. To better understand how the levees failed go to the 5 minute mark in Part I. In just a few minutes they provide video and illustrations that help you envision why the levees failed. I recommend giving it a watch. Also good is Part II in which they interview officials from LA parishes on what their evacuations plans are for a hurricane striking this summer. Suffice to say they aren’t counting on outside help.