Keyhole stone monuments of Sahara in satellite images (.kml files)

Here I propose the .kml files regarding the positions of keyhole stone monuments of Sahara. These monuments are mentioned in literature as burial sites. In the folder, besides the files obtained by means of Google Earth, .pdf documents are enclosed to illustrate the solar orientation of these monuments. One of the .kml files is named "Swallows of Sahara". Cino Boccazzi, writer and explorer, who visited several times the Sahara, reports of some stone structures having the shape of "stone flying swallows" in the region of Amguid.