Constantine is a city of bridges, and the Salah Bey Viaduct is the contemporary entry in that long habit of crossing impossible-looking ravines. Its cable-stayed span is clean and modern, but the point of seeing it is still the old Constantine drama: city, cliffs, and air beneath your feet.
It is best appreciated as part of a bridge walk rather than as an isolated stop. Compare it with Sidi M'Cid and Sidi Rached and you get a quick lesson in how each era solved the same geographical problem in a different language.