I've been reading through the Shadow World Master Atlas and I'm loving the several eras - initially being a space faring race. There's also an article on the ecology of magic by Rasyr on his
personal blog about an ancient civilisation being wiped out because they were trying to harness arcane energy at stations around the globe. It was this that caused their destruction and formed the basis for earthnodes and laylines.
I'm going to be adding things like that in my campaign that the players are going to stumble upon. I've started a concept draft image of what I'd use for such a station below and there'll be more images on
my blog in the coming months.
I'm going to try and describe the image to the players as best I can in a language the Characters would understand given their level of development and then I'm going to show the Players the picture.
I'm already keeping Arcane magic, Earthnodes and Laylines from them to be revealed at a later date, and now there's the cause to show them even further down the line - I can't wait!