My best go at a translation using Google and my limited Spanish:
"Their world destroys us. Let's build ours."
My friend Gabe and I were in Cartagena, Spain doing some work for his dissertation (I was mostly there for the coffee, wine, and tiny fried fishes). We kept seeing street art, stickers, and posters from the CNT (Confederación Nacional del Trabajo). They seem to have a pretty strong presence in the area. Checking out the map on the wikipedia entry, the Murcia regional group is the only one that doesn't span multiple Spanish regions. Perhaps that is due to the very busy port located in Cartagena through which most of the country's oil flows.