Monthly Archive 1 de June de 2021

New clues to understand the functionality of the “Torreón”, one of the most emblematic buildings of the Ulaca Oppidum (Ávila), the “Vetonic Pompeii”

A multidisciplinary team of researchers, including members of the AVATAR project, have applied a series of techniques and instrumentation from the field of geo-information and geomatics to one of the most outstanding buildings of the Ulaca Oppidum (Solosancho, Ávila), providing new information on its possible functionality. 


At the end of the 5th century BC, the Vettones, one of the most important pre-Roman populatioms of Celtic Iberia, built a series of important fortified settlements known as Oppida. These settlements generally occupied strategic sites with good natural defensive conditions, which were also reinforced by powerful walls, rammed-stone fields and moats.

The Ulaca Oppidum (Solosancho, Ávila), where the building under study is located, has been a Site of Cultural Interest (BIC) since 1995. It was one of the largest fortified settlements on the Iberian Peninsula and was inhabited during the late Iron Age (ca. 300-50 BC). It is located on an extensive granite plateau-shaped summit at an altitude of 1500 metres, on top of a hill some 250 metres above the surrounding terrain. Ulaca stands out from other Vetton settlements because of its enormous surface area (more than 70 hectares), its imposing walls, more than 3,000 meters long, and because it houses a series of very well-preserved structures, some of them exceptional in the Celtic world, such as a cave sanctuary, an initiatory sauna semi-excavated in the rock and a large ruined building known as the ‘Torreón’ (keep). This last building, which has been the subject of this research, is made up of large granite blocks that clearly differentiate it from the more than 250 domestic structures that can be seen scattered throughout the settlement. All this evidence demonstrates the importance of this exceptional site.

However, despite the extensive knowledge that exists about the Vettones and the Ulaca site, there are still some crucial aspects that remain to be elucidated. While there are numerous studies on the sauna and the altar, to date, we have lacked an in-depth analysis of the site, characteristics and possible function of the Ulaca “keep”.

In order to obtain all the information necessary for the study, the scope of the instrumentation used was both terrestrial and aerial. Thus, thanks to the use of aerial photogrammetric techniques, using a camera on board a drone (UAV), and global navigation satellite positioning (GNSS), an accurate three-dimensional reconstruction of the building has been possible. In addition, geophysical techniques such as Ground Penetrating Radar (GPR) or magnetometry, together with GNSS techniques, have provided geolocated information on the subsoil of the study area. With the first instrument, important buried constructions have been discovered around the building studied. With the second technique, it has been possible to locate different fractures in the granitic subsoil, which explain the different springs existing in the area. In this way, it has been possible to provide a superficial and subterranean view of the characteristics of the building and its surroundings.

This multidisciplinary methodological approach has provided greater knowledge of the site, revealing geometric, morphological and geological data from a more integrated perspective, making it possible to provide external and internal documentation of the building and its surroundings, without the need for destructive or invasive interventions, typical of archaeological excavations. In addition, thanks to Geographic Information Systems (GIS), the effectiveness of the “Torreón” as a possible watchtower for internal and external control of the settlement has been verified for the first time, by means of a visual basin analysis. Furthermore, as indicated above, thanks to geophysical surveys with GPR and magnetometer, photogrammetry and aerial imagery, a new scenario has emerged: the “Torreón” was erected in the most privileged area of the oppidum from the water point of view, the only corner where in summer the springs continue to provide water and the pastures remain green; besides being surrounded by other structures, in some cases of large size, which contributes to glimpse the importance of this area of the settlement and this singular building that could have fulfilled some political-religious function.

Finally, this study will facilitate future interventions to be carried out by professors and researchers of the Complutense University of Madrid in the area of the “Torreón”, as it will allow: (i) to plan, analyze and identify the most interesting areas where to carry out archaeological excavations; (ii) to optimize material and human resources, which are often limited; (iii) to increase capacities in decision-making tasks, taking into account possible day-to-day problems.

This work has been possible thanks to research funding from international, state and provincial public administrations: AVATAR Project – Marie Skłodowska-Curie, H2020-MSCA-IF- 2019 (grant agreement ID: 894785; AVATAR project); Government of Spain (European Project PCIN-2015-022); Government of Spain (National Project HAR2015-65994-R); Diputación Provincial de Ávila; Institución Gran Duque de Alba (Ayudas a la investigación sobre temas abulenses, convocatoria 2019).

Interesting links:

– Maté-González, M. Á., Sáez Blázquez, C., Carrasco García, P., Rodríguez-Hernández, J., Fernández Hernández, J., Vallés Iriso, J., … & Álvarez-Sanchís, J. R. (2021). Towards a Combined Use of Geophysics and Remote Sensing Techniques for the Characterization of a Singular Building: “El Torreón” (the Tower) at Ulaca Oppidum (Solosancho, Ávila, Spain). Sensors, 21(9), 2934.