Archaeoastronomy is a discipline apparently subject to controversy. The reason for this is that it is situated between astronomy, whose tools it uses; and anthropology, archaeology, and history, the disciplines archaeoastronomy serves and within whose epistemological framework should be integrated. Perhaps for this reason, until recently it has not received much attention by the specialists of human sciences, notably among the Egyptologist community. Hence, important issues such as the orientation of the ancient Egyptian temples and the importance of astronomy in this regard have never been addressed with the necessary seriousness and depth. The work of our group in the Nile Valley, developed between 2004 and 2010, had the intention to overcome this neglect, among many other objectives. Data from more than 400 temples have been analyzed to date to accomplish this objective. Egypt and Sudan have been scanned with the purpose of obtaining a statistically significant sample allowing us to respond clearly to the question: are the sacred buildings of ancient Egypt astronomically oriented? Our data, which confirm the hieroglyphic texts and other ethnohistorical sources, seem to undoubtedly imply this fact. We can even set up parallels for other cultures and places. Ethnographic sources are absent in modern Egypt but they are, however, available in other unique locations in the world like Easter Island or Rapanui. There, our fieldwork on island cyclopean buildings seems to confirm the information gathered from astronomical traditions still alive on site. In this essay, we will place the problem in a general context. We will focus on these two key examples afterwards. These should give evidence about how much archaeoastronomy can contribute to understanding our particular way of looking at the cosmos as human beings.