Not exactly sure what prompted these German football fans to storm the field, but two things stick out:
1) The massive amount of riot police. Are they there for every game?
2) The creative ways some of the hooligans used to try and cover their faces, so as not to be recognized.
The soccer portion of this video (from some Eastern European country, it appears) lasts only about 30 seconds as a player from one team (now known as “The Hero”) appears to score a sudden death overtime goal to win the game. Of course, fans storm the field, but then they won’t leave. The rest of the 8 minute video shows stadium security and riot police trying to restore order in the stands and clear the unruly fans who are now throwing water bottles, buckets, flairs, and anything else–including part of a security fence–at the cops. Not really sure what the final result of all of this was, but for American sports fans it gives you an interesting look into what appears to be very elaborate tactics to deal with crowds like this.