This paper addresses damage caused by Hurricane Katrina to the main Orleans East Bank protected basin. This basin represented the heart of New Orleans, and contained the main downtown area, the historic French Quarter, the Garden District, and the sprawling Lakefront and Canal Districts. Nearly half of the loss of life during this hurricane, and a similar fraction of the overall damages, occurred in this heavily populated basin. There are a number of important geotechnical lessons, as well as geo-forensic lessons, associated with the flooding of this basin. These include the difficulties associated with the creation and operation of regional-scale flood protection systems requiring federal and local cooperation and funding over prolonged periods of time. There are also a number of engineering and policy lessons regarding (1) the accuracy and reliability of current analytical methods; (2) the shortcomings and potential dangers involved in decisions that reduced short-term capital outlays in exchange for increased risk of potential system failures; (3) the difficulties associated with integrating local issues with a flood risk reduction project; and (4) the need to design and maintain levees as systems; with each of the many individual project elements being required to mesh seamlessly. These lessons are of interest and importance for similar flood protection systems throughout numerous other regions of the United States and the world.