Hurricane Katrina struck the Gulf Coast on Monday with driving rain and 145 mph winds that left hundreds and perhaps thousands of people dead, New Orleans mostly under water, and widespread damage and death on the Mississippi Coast.

Although New Orleans, most of which is below sea level, avoided a direct hit when the hurricane veered eastward at the last minute, two levees gave way on Tuesday that caused massive flooding. Many residents had fled before the storm, but those who could not, or would not, found themselves in a desperate situation.

There was no electricity or running water and little food and bottled water.

Some residents were stuck on roofs. The Superdome, where about 15,000 people sought refuge, became a sweltering cesspool as electricity failed and plumbing clogged and overflowed.

By mid-week, many parts of the city had devolved into lawlessness. Looting was widespread, and there were reports of armed gangs. And although floodwater began to recede as the week wore on, it was clear that it would be many weeks before the city would be dry enough to assess full damage.

Larger contingents of National Guard troops, some from other states, began to restore order on Friday, and tens of thousands of displaced residents began to be relocated -- many to Texas.

Early relief efforts were spotty. President Bush admitted before he visited on Friday that they were inadequate.

Although New Orleans suffered incalculable human and property damage, the Mississippi Gulf Coast was devastated, as well. Nearly all structures were destroyed along a 50-mile swatch of coastline that includes Biloxi -- and its popular floating casinos -- and Gulfport.

About 150 people have been reported dead, a number that is expected to rise.

Larry Harrison carries Jaquin Johnson, right, and Heaven Girod through floodwater in New Orleans on Tuesday.