Thousands of years before the advent of modern medicine, ancient Peruvian surgeons in the Andean highlands practiced a sophisticated form of trepanation, or skull surgery. At sites dating back to around 400 BCE, archaeologists have unearthed evidence of these procedures, where patients' skulls were drilled or scraped using instruments made of obsidian and bronze. Astonishingly, the survival rates for these ancient surgeries appear to have been higher than those recorded during the American Civil War, a period centuries later with far more advanced medical knowledge. This striking success, achieved without any understanding of germ theory or antibiotics, highlights the remarkable skill and empirical knowledge of these early Andean medical practitioners.