In the wake of Hurricane Katrina, much of New Orleans is underwater, as shown in the top image, made on August 30 by NASA's Terra satellite.

The lower image, made two days before Katrina came ashore, shows the city between Lake Pontchartrain and the Mississippi River.

As much as 80 percent of the city is flooded after levees failed to hold Katrina's massive storm surge back. The flooding is getting worse as water slowly seeps into the city from the lake.

The images are shown in false color to make water visible against the land. Water is black or dark blue where it is colored with mud, vegetation is bright green, and clouds are light blue and white.

See More About Hurricane Katrina
• New Orleans Flooded in Wake of Hurricane Katrina
• Hurricane Katrina Smashes Gulf Coast
• Photo Gallery: Hurricane Katrina
• Video in the News: Hurricane Katrina Animation
• Hurricane Katrina: How You Can Help

• See More Photos in the News
• See Today's Top News Stories
• Get Our Free Photo Newsletter