Catalunya had a new estatut d'autonomia, something like a constitution with rights and laws approved, and it was ok for Catalunya and Spain government, but after a year PP who is the popular party(right side) won the elections of Spain they made it illegal (same laws are on other communities so no sense to do it just in Catalunya if they think it's illegal).
President of Catalunya asked to recover that with no luck, so he asked to do a referendum since a lot of people was asking to leave Spain. Obviously the Spain political party said that was illegal too, and Catalunya set a query to ask Catalans if they want to leave Spain on 2014. Result was Yes, but it was not official, what Spain did, was ban the president of Catalunya and force Catalunya to new elections. The next president tried to get a referendum with no luck for 3 years, he get no referendum and no solution to try to put peace on this matter, after that they did a new "query" saying that it will be a legal referendum in Catalunya (not Spain).
Yes won again (almost 3 million votes when there's less than 5 that could vote) and what Spain did, was sent 10.000 police men that kicked and laughed over all the people who tried to vote (elder people, womans...)when everyone was doing it pacefully. You can see plenty of videos and images on youtube searching for 1 octubre. 1000 injured people, one guy lost an eye and one had a heart attack and died in front of a college.
Catalunya tried to get a real referendum, a third one to validate and make it a real one but Spain said no and put two people that were on the social movement (everything paceful) in jail. After that, Catalunya president said that independence was real (even it wasn't real from a legal point of view) and they put all the political party that was ruling Catalunya in jail, with 7 politics who left to other EU countries before police asked for arrests.
After two years on jail, the sentence is here and they are going to spend 9-13 years in prison, when there was not a single moment of violence in all the process.
Monday started with some paceful rallies but a guy lost an eye and another one lost a testicle because of the police violence, so on tuesday people started to reply in violence too that's what you're sawing right now.
Today a police car run over two guys, who were on a riot and then they get out the car to kick the guy on the ground which is surreal. I don't think this is gonna end like a civil war or anything similar, but someone needs to put a stop on this or it could get worst.