From the heaps of places that are trying to inscribe I visited La Union near Murcia. The first sights I saw were the typical rundown, forgotten and left behind buildings of a mining landscape. I knew I was at the right place. The first stop was at El Rojo, a lake now so red from the acid resulting from the mining. This isn't a tourist spot and the lookout even had a big no parking notice plus the typical danger sign, but it was only a few meters to get a good view. This all wasn't so much to see so there was surely something they are trying to inscribe?
It's a landscape so you get a lot of buildings. Go into the town proper and you can find the old market, a pretty building, and a few casas & villas from former head honchos in the mining industry. I wasn't all impressed but it didn't take much of my time.
I can't speak for all the heritage sites but this seems more of a national importance rather than a worldly one.