Rover images confirm Jezero crater is an ancient Martian lake

Perseverance’s initial images are the first ground-based evidence that Mars may have once housed a delta branching out into a lake in Jezero Crater. This study informs where Perseverance will now go sample rock, looking for signs of ancient life.

Perseverance rover confirms existence of ancient Mars lake and river delta

NASA's Perseverance Rover Finds Signs of Epic Ancient Floods on Mars