New Orleans is a city at the bottom of a bowl, surrounded by a rim of earthen levees and concrete walls designed to keep nature out. Despite efforts to protect it, the city is more vulnerable now than ever. Two years after Katrina, the U.S. Army Corps of Engineers says the levees are back to pre-hurricane strength. But much of the population is still displaced. Here's a look at the levee system protecting New Orleans and where people are living since the devastation in 2005. You will need to install or upgrade your Flash Player to be able to view this Flash content. Also, Javascript must be turned on.

TIME graphic by Feilding Cage, Joe Lertola,
Jackson Dykman and Kristina Dell
SOURCES: Greater New Orleans Community Data,
Army Corps of Engineers,
National Science Foundation, U.S. Geological Survey,
Dean Whitman, Ph.D., Florida International University, New Orleans Regional Transit Authority,
New Orleans Metro Association of Realtors, ESRI 2005 and 2007 Demographic Data