Europe's Oldest Subterranean Structure? New Chronological and Structural Insights from Dry-Stone Wall in the Ravne 3 Tunnel Complex, Visoko, Bosnia-Herzegovina

This study presents groundbreaking archaeological and geochronological findings from the Ravne 3 Tunnel Complex in Visoko, Bosnia-Herzegovina. Through stratigraphic analysis and precise radiometric dating, the article documents the existence of an intentionally constructed dry-stone wall (Wall No. 1) located beneath undisturbed speleothem formations. Uranium-Thorium dating of the stalagmite growing atop the wall yields a minimum age of 19,000 ± 1,000 years, while radiocarbon analysis of nearby speleothem layers provides a calibrated date of 26,200 ± 250 years BP. These results suggest that the tunnel system predates the Late Glacial Maximum, making it one of the oldest verified subterranean human structures in Europe. The presence of architectural continuity, sealed passages, and mineral deposits implies that the tunnels were intentionally constructed and later abandoned or preserved. These findings challenge conventional models of European prehistory and support the hypothesis of advanced construction capabilities in the Upper Paleolithic era.