The flood is the most significant to hit the lower Mississippi River valley since at least 1937.

CNN: Mississippi governor urges caution as river crests

The flood is the most significant to hit the lower Mississippi River valley since at least 1937 and has so far affected nine states: Missouri, Illinois, Kentucky, Tennessee, Ohio, Indiana, Arkansas, Louisiana and Mississippi.

CNN: STORY HIGHLIGHTS

And in late 2009, a federal judge ruled that the U.S. Army Corps of Engineers' mismanagement at the Mississippi River-Gulf Outlet was the cause for flood damage in the Lower Ninth Ward and St.

CNN: New Orleans is storming back