Transport Blog offers another reason to visit Bilbao
The metro system has a couple of other items of note. For one thing, rather than being at or below river level, in some cases the metro line has instead been dug inside the steep banks of the river. An interesting consequence of this is that whenever there is a side valley going off the main river valley, the metro line comes out of the side of a hill, goes through an elevated section over the tributary river, and then enters a hill on the other side of the tributary valley. It is quite spectacular.Seattle is building an (elevated) monorail system. As Seattle is a hilly city in a picturesque region (Mount Rainier etc etc) the views from the cars should be spectacular. Such a benefit should not be underestimated in creating ridership. I grew up riding the subways of Manhattan and every time I hear one of my neighbors suggest that it is too bad that we couldn't have afforded tunneling to build a subway, I have to wonder if she has ever ridden a subterranean system on a daily basis. I think that it is a grim experience and the visual stimulation of the Seattle system will be another intangible but very real benefit of elevated transit. Actually maybe not so intangible, as once we have built the system, we want people to ride it in order (among other things) to pay for it.