A moat dating back 2,200 years has been by students working in Tarragona, Spain. Within the practical work of the degree, about one hundred students carried out field walking, with metal detectors, aerial photography and geophysical surveys. Results obtained from one of the techniques —the electrical tomography— showed some soil anomalies.
Evidence that stone tools were recycled by ancient humans has been found in Tarragona, Spain. "In order to identify the recycling, it is necessary to differentiate the two stages of the manipulation sequence of an object: the moment before it is altered and the moment after. The two are separated by