An anonymous reader writes "An orbiting spacecraft has sent back new evidence for the presence of water on Mars. Scientists long have debated whether water flowed on the red planet, with evidence increasing in recent years. The presence of water would raise the possibility of at least primitive life forms existing there. Images from a camera aboard NASA's Mars Reconnaissance Orbiter show alternating layers of dark- and light-toned rock in a giant rift valley."
I've never been canoeing before, but I imagine there must be just a few
simple heuristics you have to remember...
Yes, don't fall out, and don't hit rocks.