It’s a road on a man-made land bridge before and after this aqueduct. In this shot here, it’s a bit hard to see, but the road is actually on a slight angle to make more room for the aqueduct. The walls around the road are only for this section, as out of frame the road is almost certainly on top of your bog standard land bridge.
What in the gosh darn condescending non sequitur is that? I have a special kind of dislike for people who, instead of trying to promote learning for anyone and everyone at any stage, instead choose to ridicule people for having missed some trivial detail that has about as much in common with Bash as does COBOL (basically nothing). Web scripting is, unsurprisingly, its own skill, and it’s very, surpassingly, extremely, stupendously, and obviously conceivable that someone could have years of Bash experience but only recently started putting around with scripting for things like API access or HTML parsing. But you should know this already. :)