What is football/soccer's most intense rivalry?

[PorkChop]

Watched this earlier about the Rangers / Celtic rivalry - I don't think it's the most intense in football, but it's pretty big. They talk about a 15 year old Celtic fan having his throat cut simply because he was a Celtic fan, and the history of violence between the two teams.

I remember when Luis Figo moved to Madrid from Barcelona he had bottles, coins, golf balls and pig's head thrown at him when he went to take corners and throw-ins. The Fenerbahce vs Galatasaray rivalry is pretty intense too. I think football's rivalries are easily bigger and more intense than the rivalries in any other sport.

[AkydefGoldberg]

Rangers vs. Celtic - probably don't think it's as intense as it used to be in the 90s but still evokes alot of emotions.

The other two that Porky mentioned but also:

Lazio vs. Roma
Boca Juniors vs. River Plate

There are other rivalries (United/Liverpool, AC vs. Inter Milan) that are hard-fought and competitive but not intense to the point there is hatred.

[HFX]

Roma vs Lazio is always the first one that springs to mind. Those guys scare me badly.

[SlightlyJames]

Came here to say the Old Firm, but that's the one I've had the most exposure to. Got to say most people I know aren't like that (it's good for a banter but none of that sectarian nonsense) but I have spoken to some right bastards on both sides.