Under the North Sea and the Baltic Sea, approximately 1.6 million tonnes of shells and mines have been lying since the end of World War II. These munitions, many of which are now corroded, release explosive compounds and toxic substances into the surrounding water. German researchers have discovered traces of TNT, a powerful explosive, in the flesh of wild mussels, sometimes kilometers away from where the weapons were originally dropped. This discovery highlights the long-term environmental impact of wartime activities, as the remnants of battles continue to affect marine ecosystems decades later. Approximately 1.6 million tonnes of conventional ammunition and 5,000 tonnes of chemical agents have been resting at the bottom of the German North Sea and Baltic Sea since 1945. Over time, the metal casings of these weapons have rusted and cracked, allowing substances like TNT, toxic compounds, and heavy metals such as mercury to seep into the seawater. The Baltic Sea is particularly concerning because it is connected to the Atlantic Ocean only through a narrow channel, limiting the renewal of its waters and allowing pollutants to remain concentrated for extended periods. Mussels, which are filter-feeding mollusks, play a crucial role in this issue. They continuously pump seawater through their bodies to feed, absorbing any particles or chemicals suspended in the water. Studies conducted along the German coast have detected TNT and its derivatives in the water, sediments, and tissues of various marine organisms, with mussels being the first to show these traces. While the concentrations of these compounds are generally below levels considered dangerous for human health, some areas near the densest clusters of submerged munitions have seen levels that are dangerously close to these thresholds, raising concerns about potential contamination of the food chain. In response to these findings, German authorities have taken action. The federal minister for the Environment, Steffi Lemke, has launched an emergency program funded with 100 million euros to systematically demine the most contaminated areas in the North Sea and Baltic. This issue extends beyond Germany, as similar wartime remnants are likely buried in other European seas, such as the Adriatic Sea and the English Channel. The full environmental impact of these submerged arsenals remains largely unknown, underscoring the long-lasting consequences of conflicts that occurred decades ago.