Shellmiddens as landmarks: Visibility studies on the Mesolithic of the Muge valley (Central Portugal)

•Emergent social complexity has been suggested for the Muge Mesolithic shellmiddens.•We attest visibility as determinant in Mesolithic settlement and social organization.•Different visual properties between riverbanks reveal social/functional diversity.•Muge middens might represent the first evidence of monumental locales.

Recent studies on the Mesolithic shellmiddens of the Muge valley (Central Portugal) indicate that these sites must have had, by their size, aspect and integration in an increasing socially complex cultural system, a major impact on the landscape as monumental anthropogenic features. Their role as landmarks and, most probably, as centers for different social/functional units is expected to be manifested in a considerable visual prominence on the terrain. This paper focuses on the use of geospatial techniques and statistical analysis to assess visibility as a determinant factor for Mesolithic settlement location and social patterns in Muge. Results confirm a considerable importance for features such as visual prominence, intervisibility between several settlements and visual control of the environs. A significant dichotomy in the visibility properties of both riverbanks mirrors differences in the archaeological record of sites and suggest that some of these sites might have been special locales with social impact as cultural landscapes.