The provenance of the stones in the Menga dolmen reveals one of the greatest engineering feats of the Neolithic.

The technical and intellectual capabilities of past societies are reflected in the monuments they were able to build. Tracking the provenance of the stones utilised to build prehistoric megalithic monuments, through geological studies, is of utmost interest for interpreting ancient architectures as well as to contribute to their protection. According to the scarce information available, most stones used in European prehistoric megaliths originate from locations near the construction sites, which would have made transport easier. The Menga dolmen (Antequera, Malaga, Spain), listed in UNESCO World Heritage since July 2016, was designed and built with stones weighting up to nearly 150 tons, thus becoming the most colossal stone monument built in its time in Europe (c. 3800-3600 BC). Our study (based on high-resolution geological mapping as well as petrographic and stratigraphic analyses) reveals key geological and archaeological evidence to establish the precise provenance of the massive stones used in the construction of this monument. These stones are mostly calcarenites, a poorly cemented detrital sedimentary rock comparable to those known as 'soft stones' in modern civil engineering. They were quarried from a rocky outcrop located at a distance of approximately 1 km. In this study, it can be inferred the use of soft stone in Menga reveals the human application of new wood and stone technologies enabling the construction of a monument of unprecedented magnitude and complexity.