Underwater archaeologists using high-resolution sonar have discovered a submerged military fortification along a strategic bend of the Yangtze River, dating to the Warring States Period. The structure consists of a half-mile-long stone wall reinforced with iron stakes, designed to intercept naval incursions and protect a major inland trade city. Excavations of the riverbed have also revealed several massive stone platforms once used to support early heavy trebuchets.
Researchers recovered hundreds of bronze spearheads and intact ceramic grenades filled with proto-incendiary mixtures, suggesting a high level of advanced riverine warfare. The site represents the most complete defensive river works ever found in China, offering a unique glimpse into the intense geopolitical rivalries and engineering ingenuity of the era before the unification under the Qin Dynasty.