they used to possess names and many of the names can be found on plaques like this. I haven't been able determine the origin of the name (which means "the Harem"). However, it clearly depicts a canopy under which a cross-legged male figure sits on a pillow, fanned by two girls wearing veils. Perhaps this was once the "red-light district?"
King Phillip II of Spain in the 17th Century. He wanted to promote commerce in the colony, and rightly thought the covered areas would protect itinerate merchants and their customers from both rain and hot sun. As a consequence, virtually every plaza in Mexico possesses an area like this.