This isn't the first time that NASA has reported discovering evidence of water on Mars.

Just over a year ago, NASA announced that the had taken images showing evidence of past water flows on the Martian surface. NASA scientist said the planet might hold frozen water just beneath its surface.

William Dietrich, Curiosity's science co-investigator, called this latest discovery a turning point.

"This is the first time we're actually seeing water-transported gravel on Mars," he said. "This is a transition from speculation about the size of streambed material to direct observation of it."

Dietrich noted that scientists now have visual evidence of particle collisions during the transportation of water, a finding that shows there was a "vigorous" water flow and not a small amount of water seepage.