An exceptional glacial melting event, dating back to the Medieval Warm Period, was recently discovered in Antarctica, specifically on northern Victoria Land. The study, published in the journal Communications Earth and Environment, revealed a never-before-observed phenomenon: between 900 and 989 AD, a sudden climatic warming caused a glacial melt that left deep traces in the Antarctic landscape. The project, coordinated by Emanuele Forte (University of Trieste) and Mauro Guglielmin (University of Insubria), along with other experts, documented intense fluvial erosion and sediment transport on the glacier surface, which carved a channel at least 4 kilometers long. This event changed the stratigraphy of the glacier, accumulating sediment and creating a graded deposit, indicative of a gradual slowing of water flow. Unlike the current melting phenomena observed elsewhere in Antarctica, this medieval event occurred during a period of natural warming and is unique: in fact, today the glacier in question is permanently snow-covered with no signs of surface melting. This discovery offers new insights into the stability of Antarctic glaciers and demonstrates how even brief episodes of warming can cause lasting transformations in the glacial landscape. The results suggest that Antarctic glaciers are extremely sensitive to sudden climate change, with implications for the future as well, in view of global warming and climate change-related extreme events. The study was conducted under the National Antarctic Research Program (PNRA) and funded by the Ministry of Universities and Research (MUR).