In 1986, the Colombian archaeologists Clemencia Plazas and Anna Maria Falchetti, defending this thesis, showed that the ridges and channels built on the banks of San Jorge (covering about 50000 sqkm and are the largest of the river networks of Hispanic America) were the work of the pre-Columbian Zenú society, and that the San Jorge Valley was inhabited by a highly technological society can be seen as pottery and jewelry found on the banks of the river.