Mars Express discovered an ancient system of underground lakes on Mars.

There is a hypothesis that liquid water was previously present on Mars. There is evidence in her favor

Traces of a liquid river discovered by the Mars Express apparatus in the Nili Fossae region, where there is a clear boundary between the two hemispheres of the Red Planet.

Now researchers have discovered newevidence of the existence of liquid water on Mars in the past. They analyzed images of 24 impact craters in the northern hemisphere of Mars, from 1.4 to 3.1 km in depth. As a result, it turned out that along with most of them there are valleys formed by water flows, and in some craters - deep canals.

15 craters had fan shapes similar toriver deltas. Some had channels that looked like branching tributaries. Their surface turned out to be flat - probably, such a relief was formed by the water accumulated in them. At 16 craters, accumulations of rock were found that looked as if they had been formed by landslides.

ESA

Previously Russian-European space probeExoMars-TGO has compiled detailed maps of the distribution of water on the surface of Mars. Scientists, based on his data, compiled the first complete maps of water both on Mars and under its surface.