NASA reports, that using the CRISM spectrometer of the Mars Reconnaissance Orbiter (MRO) was determined that the dark stripes on Mars surface is the trails of the liquid water.
These dark stripes were first discovered five years ago, in 2010. But only now they were truly researched.
During all the time of Mars exploration we already have a lots of circumstantial evidence of liquid water presence. But this evidence is much more serious.
Researchers thinks that in the warm season on Mars, when temperature raises up to 20° C on the planet’s surface flows streams of salt water. Water then evaporates and left these dark stripes.