Archaeo-astronomy: a reality check

Many megalithic structures around the world may indicate an early interest in celestial phenomena. Unfortunately, many charlatans and pseudo-scientists attach outrageously implausible claims to such structures in sensationalistic publications. I shall explain what archaeo-astronomy is, then briefly review a few (out of many) mainly megalithic structures indicating astronomical interest in the Neolithic period. The published evidence will be put on geographical and temporal planes, attempting to determine whether the astronomical interest developed separately at different sites, to achieve an almost global spread, or whether it originated at a single site from where it diffused globally.