NASA's Perseverance Rover Discovers Evidence of Ancient Lake on Mars. In a groundbreaking discovery, NASA's Perseverance rover has uncovered proof of a massive lake that once existed on Mars. The finding, which sheds new light on the Red Planet's watery past, has significant implications for the search for life beyond Earth. According to scientists, the ancient lake, which is believed to have existed around 3.5 billion years ago, would have provided a suitable environment for microbial life to thrive. The discovery is set to be a major milestone in the ongoing exploration of Mars, with NASA's Perseverance rover continuing to send back valuable data from the Martian surface.