Their non-invasive analysis, carried out with drones,[15] shows that the 250-metre (820 ft)-long tumulus is of human origin and probably built on the model of the Chinese imperial tombs present in Xi'an. In addition, the expedition notes that this mound is still the subject of religious rites and pilgrimages of the surrounding population.[16][17] This expedition did not give rise to any scientific publication by Pierre-Henri Giscard because it was made without authorization, and without informing local authorities. Indeed, besides the fact that the access to the area around Burkhan Khaldun is strictly controlled, the sacredness of the tomb for the Mongolian government and the population makes it impossible to explore.[18][19] Pierre-Henri Giscard mentioned that more details about his research may be published posthumously.[20]