Take a look through Europe's top leagues and you'll come across some of the most famous rivalries in world football.
From Lazio versus Roma in Italy, to the Old Firm games in Scotland - these matches are steeped in both history and hatred in equal measure.
Whether it's down to political differences or simply geographical, these fixtures have the ability to produce atmospheres of genuine hostility as much as they do moments of on-pitch magic.
But of all the rivalries in England, there are few that come close to matching the hate, passion and importance of Manchester United versus Liverpool.
The two giants of English football clash on Sunday afternoon, both looking for three points but for very different reasons.
While United search for a fourth consecutive league title, Liverpool are stuck in a desperate battle to secure Champions League football next season.
And although the rivalry has centred around footballing reasons in recent years, it's roots go far beyond the realms of football.
The two cities originally conflicted during the industrial revolution, more than 150 years ago. Liverpool was famous for it's port while Manchester could boast a booming manufacturing industry.
But when the building of the Manchester ship canal resulted in job losses at Liverpool's port, a huge resentment from the city of Liverpool towards Manchester was born.
And when the two clubs were formed during the late 1800s, the ill-feeling between the people of each city was inevitably transmitted to the supporters of the newly-formed teams.
With such a personal note to the rivalry, it's unsurprising that United-Liverpool games are now some of the most dangerous fixtures in all the football calendar.
With early kick-offs to discourage too much pre-match drinking and a huge police presence on show, the authorities do all they can to avoid clashes between rival fans.
But despite all of these measures, fighting between Mancs and Scousers has become almost expected.
It's not on the same level as the hooligan glory days of the 1970s and 80s, but in a game with so much long-standing hatred, some 'fans' will always find a way to express their feelings.
Add to the mix players like Steven Gerrard, Jamie Carragher, Gary Neville and Wayne Rooney - all of who have publicly announced their dislike of the opposing club, and you have all the ingredients for a very feisty encounter on Sunday afternoon.
Sir Alex Ferguson's men will be heavy favourites, but with both clubs level on 18 league titles, Liverpool will be doing all they can to ensure United don't take their place in the record books.
- Joe Strange