The culture was based on farming, but metal-working was considerably advanced, and by the end of the period long-range trade within the area and with Mediterranean cultures was economically significant. Social distinctions became increasingly important, with emerging elite classes of chieftains and warriors, and perhaps those with other skills. Society was organized on a tribal basis, though very little is known about this. Only a few of the largest settlements, like Heuneburg in the south of Germany, were towns rather than villages by modern standards.