Discoveries of new structures in the Valley of the Temples in Agrigento, Sicily Archaeological excavations can unearth valuable insights into ancient civilizations. However, digging an entire site is time-consuming, expensive, and risks damaging undiscovered artifacts or structures.

Fortunately, geophysical techniques provide archaeologists with non-invasive tools to investigate sites beneath the surface. A recent study applied soil-penetration geophysical methods in the renowned ancient Greek city of Akragas, now known as Agrigento in Sicily, Italy.

The techniques revealed buried structures, subsequently confirmed through excavations. This multidisciplinary approach optimized resource utilization, leading to new and exciting discoveries that enhance our understanding of architecture and religious practices in ancient Akragas.

Founded in 580 B.C. along the southern coast of Sicily, Akragas quickly grew into a prosperous metropolis, renowned for its massive temples, colonnaded streets, and luxurious lifestyle supported by abundant farmland.

However, the city faced invasions and destruction before ultimately falling under Roman rule in 262 B.C. Today, tourists visit the archaeological park of the Valley of the Temples in Agrigento to admire the impressive stone columns and pediments of the surviving temples.

Despite past excavations, much remains unknown about Akragas, especially in unexplored areas outside the valley. One such site north of an ancient street called Plateia I-L holds enormous potential given the city’s richness and importance. However, without subsurface research, archaeologists lacked knowledge of buried remains that could reveal new insights.

To address this, researchers from the University of Bordeaux-Montaigne collaborated with Italian authorities to conduct geophysical studies in a 3,000-square-meter study area. The goal was to non-invasively map subsurface features before excavating specific areas, optimizing resources and minimizing damage.

The team divided the site into four sectors and employed two primary geophysical techniques: electromagnetic surveys and electrical resistivity tomography. Electromagnetic surveys use induced electrical currents in the soil to detect physical anomalies related to buried objects, such as walls, covering large areas quickly.

Electrical resistivity tomography more precisely determines buried elements by measuring subsurface resistivity variations. Both techniques identify remains through contrasts in physical properties compared to surrounding soils and rocks.

Previous geophysical archaeological studies informed the team’s analysis. Common anomalies related to walls and structures exhibited distinctive resistivity profiles compared to natural terrain. Features like hearths or furnaces also stood out. Meanwhile, variable factors such as vegetation or geology required consideration. Over four weeks, researchers meticulously measured all sectors, first using the electromagnetic method for an overview and then applying electrical resistivity tomography in selected areas of interest for higher-resolution data.

Processing and interpreting the geophysical results revealed numerous subsurface anomalies characterized by significant resistivity variations. Given their shapes, sizes, orientations, and locations in relation to known structures, the team attributed many anomalies to buried walls and related human features. Two particular areas in the northwestern and central parts exhibited extensive vegetation interfering with resistivity profiles, but otherwise, patterns supported large underground structures.

These findings informed the decision to conduct initial test excavations in an area identified by electrical resistivity tomography. Digging confirmed the presence of an extensive buried wall over 3.5 meters long constructed with large limestone blocks, matching the geophysical resistivity profile. Additional excavations determined that the wall overlapped with an earlier wall of similar orientation, built using large stone blocks still measuring over a meter in length after exposure to degradation.

Analysis of ceramics associated with the walls indicates probable construction dating between the 4th and 2nd centuries B.C., during the Hellenistic period, with the earlier segment possibly from the 6th to 4th centuries B.C., the classical period. Given the monument’s features and location near an entrance to an ancient sanctuary with circular altars, researchers believe it had religious significance within Akragas.

In the future, additional excavations will help determine the wall’s function, refine its chronology, and establish its relationship with nearby structures. Sharing knowledge from this successful integrated study-excavation campaign will support refining geophysical archaeological applications in Italy and benefit future research in Akragas as exploration continues in unmapped areas harboring undisclosed secrets of this renowned ancient city.


Sebastiano Imposa, Sabrina Grassi, et al., New discovery of an ancient building in Akragas (Valley of Temples, Agrigento, Italy) through the integration of geophysical surveys. Journal of Archaeological Science: Reports, Volume 53, February 2024, 104368.

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