During the last decade (starting in 2005), the OAS Project has been run, with the support of the Spanish research agencies. Within its framework, research on cultural astronomy has been developed for a series of ancient cultures from the Atlantic Islands to the Arabian Peninsula with the Meditterranean Sea as the pricipal axis of the project. A catalogue of studies has been performed in a set of cultures such as the Megalithic Phenomenon, ancient Egypt, Middle East Bronze and Iron Age civilizations and the Roman World, among many others. In this essay a general scope of the project and a series of most interesting outcomes will be presented. The evolutionary ties of the megalithic monuments of the Iberian Peninsula and elsewhere, the pattern of orientation of Egyptian temples and skyscaping practices within the Hittite, Commagenian or Nabataean cultures, among others, will be shown; finishing in a comprehensive, statistical and comparative study of the orientation patterns of thousands of ancient monuments of the Mediterranean region. Finally, a sketch of our most recent, still ongoing, research on the astronomical and non-astronomical practices used in the planning of cities in the Roman World will be a compelling and promising closing remark of our analysis.