Scientists See Evidence of Underground Lakes System on Mars

An image of a ancient northern ocean on Mars released by the European Space Agency in 2012. A new research study details the first direct geological evidence for a 'planet-wide groundwater system' explaining Mars's watery history. C. Carreau/ESA

BERLIN—Scientists say images of craters taken by European and American space probes show there likely once was a planet-wide system of underground lakes on Mars.

Data collected by NASA and ESA probes orbiting the red planet provide the first geological evidence for an ancient Martian groundwater system, according to a study by researchers in Italy and the Netherlands published in the Journal of Geophysical Research.