Changes

Roofs and similar structures are quite fine sleeping places. Sleeping in abandoned houses is recommendable although it is considered a crime, "trespassing" unless you have a banner with the squatting "N" hanging from a balcony, window etc. The cops are going to put this down and inform the landlord. If they do not want you to stay and if you have been there for less than a week they can evict you right away. So in case you want to stay somewhere for less than a week having a banner is most likely not worth the hassle... You can just stay in a squat that has already gone through the registration process. Most of those houses are in Barcelona. In order to find a place to stay there you can simply look up the online version of the local squatter's newspaper "Info Usurpa" and attend the next happening in one of the locations where you can ask for sleeping places among the guests.