TIME chronicles the story of the greatest natural disaster in U.S. history in "Hurricane Katrina: the storm that changed America". Here, in stunning photos, is the terrible tale of Katrinaś deadly wrath and savage aftermath. Here is Americaś Gulf Coast - from New Orleans to Biloxi and Gulfport, Mississippi - in ruins. Here are the struggling survivors and their valiant rescuers, the looters and the police who fought to control them, the homeless refugees who poured across the southeast and the resourceful agencies that took them in. Exclusive portfolios by TIME phographers reveal the scope of the disaster, and unforgettable accounts of natureś power and manś resourcefulness. An extensive timeline shows the nine days descent into chaos, and informative graphics illuminate the science of the story; how hurricanes form - and why New Orleans flooded.