Exploratour - The Surface of Mars
This is an image showing evidence of Martian flooding.
Click on image for full size
Image from: NASA
Click on image for full size
Image from: NASA
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Martian Lakes
Separate from the Martian outflow channels, or the river valley networks, are large lakes (600 km, or ~1000 miles across). These lakes are evidence of times when there was a large release of water in the form of a flood.