A high-resolution LiDAR mapping project covering the dense Ardennes forest has identified a sprawling network of over 2,000 previously unknown iron-mining pits and smelting sites. Dating back to the La Tène period, this "industrial megalopolis" suggests that the local Celtic tribes operated a massive, coordinated iron production industry long before the Roman conquest of Gaul.
The survey also revealed fortified hilltop settlements and a complex system of paved tracks connecting the mines to regional trade routes. This discovery redefines our understanding of pre-Roman European industry, proving that the Celts had mastered large-scale resource extraction and logistics across rugged terrains.