These bumpy nodules were formed by minerals left behind as groundwater was drying out on Mars billions of years ago. NASA’s Curiosity rover captured images of these pea-size features while exploring geologic formations called boxwork on Aug. 21, 2025. Credit: NASA/JPL-Caltech/MSSS A rugged Martian landscape that resembles a giant spiderweb when seen from orbit may hold important evidence about the history of water on ancient Mars. For roughly six months, NASA's Curiosity rover has been studying