This street is only about two meters wide. Streets of this width are common in African souks and medinas. See, for example, some of the streets in the Morocco section. Like this street in Algiers, many of the streets in Morocco's Fes-al-Bali (believed to be the largest contiguous carfree population in the world) are comparatively steep and require steps. In Marrakech, built on quite flat land, they are not needed, and the streets are by comparison less interesting.
The delivery of freight in these streets is very difficult. The only real alternative is the use of donkeys, which can negotiate the steps without special difficulty. Emergency access is simply impossible, and I can't imagine what is done in the case of a fire. Medical evacuations would only be possible by stretcher. I doubt, therefore, that we will ever see construction of streets like this one again.
Notice that the buildings are corbelled out over the street and even come quite close to touching one another. In hot climates where the noonday sun is to be avoided at all costs, corbelled buildings provide effective shading of the streets below and allow them attain the necessary width.
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