Curious to hear if these exist in other countries outside of Europe and South America. They are gangs connected with the football clubs. Some like to fight each other. Some in some countries have a say in what happens at the clubs. If they don't like a manager, they will tell fans to stay away from the home games. Until the manager is sacked. Used to be bigger in the UK in the 80's until they cracked down on it. Video shows what happens when 20,000 German fans show up in London. Only 2,000 had tickets for the game. This was a gesture at the home fans, that they are been insulted on their home patch.