Each of them constitutes one burial chamber or two of the same level, in most cases one of them above the other. The ceiling of the burial mound consists of sheets of stones. After closing the grave on its occupant, soil used to be heaped on the stones until it took the shape of mounds. The doors of the graves are on the western side, and this is linked to religious beliefs. In cases where skeletons were discovered in the graveyards, it was found that the dead was placed on its right side, with the torso facing the north-eastern direction, and all of them were in a squatting position, like the embryo in his mother's womb.
Burial mounds are artificial hills consisting of sand mixed with gravel.
In some types of mounds there are relatively medium-sized and large stones. In the middle of these mounds is the centrally located burial chamber. Bahrain's burial mounds are estimated to be more than one hundred thousand archaeological mounds which occupy as much as 20 square miles of land. These burial mounds date back to different historical periods, the earliest of which is the first half of the third pre-historic millennium. Excavation and digging work started in 1879 and since then excavation and digging by archaeological missions have been going on continuously.