Depending on the time of construction, retaining walls are made with or without cement. The original way is without dry stone walls. They are held together by gravity and the choice of stones. The largest stones are at the base, and the wall is thinner at the top (like a pyramid). Without mortar, there is no need for water drainage, which occurs naturally.
The typology with cement is an attempt at renovation. It is not the original way of doing things. However, it is interesting to represent and present them here because they appear in many places within the village.