@Tubemeister @paneerakbari @sailboat @Catvalente I looked this up, and even if we took the easiest mountain passes, the highest point the canal would have to go through would be well over 300 meters above sea level. As the water in the canal must be, well, at sea level*, that would mean digging a ditch some 350 meters deep, 350 meters wide and 100 kilometers long. Many many dig dig indeed.
* We can’t use locks to lift the ships up as there is no (economically feasible) way to get the water up to the higher levels. In Panama there’s a conveniently located lake to tap into, but in Arabia, oddly enough, those are harder to come by.