Every time there's football matches between Rangers and Celtic in Glasgow, they send out the riot police because shit can get violent very easily.
On the other side of the central belt in Edinburgh, there were plans to have separators on the trams to keep Hibs and Hearts fans separate.
London tube trains have to skip some stations on match days to prevent certain fans mixing and fighting. Doesn't stop them banging on the tube trains. Arsenal tube station has bars specifically designed to stop rival teams fighting each other on the stairs.
Millwall fans are so notoriously violent when the Dockland's light railway was being built, rather than naming a station "Millwall" they named it "Mudchute". Do you know how bad you have to be to have your area's station named after a euphemism for arsehole.
Autistic person here: No. No, what the fuck?