Billions of years before human eyes could witness it, Mars endured a relentless celestial bombardment—and unlike Earth, it never forgot. NASA's Perseverance rover has read that memory in a 245-foot stack of ancient rock at a formation called Broom Point, where layers of impact debris from repeated asteroid strikes have rested undisturbed for more than 3.9 billion years. Because Mars lacks the plate tectonics that have erased Earth's earliest geological chapters, this Martian archive may ultimately tell us as much about our own planet's violent origins as it does about its neighbor's.