Two of world football 's biggest fixtures take place on Sunday . Liverpool play Man United at Anfield with top four place at stake . Barcelona meet Real Madrid at Nou Camp in top-of-the-table clash . Around 700m will watch Premier League encounter around the world . Real Madrid lead the revenue charts with wealth of £459.5m . Both they and Man United sell 1.5m replica shirts each year . Real have won the most trophies and have most Twitter followers . READ : Two fans take part in Q & A ahead of Sunday 's Barcelona showdown .
Two of world football 's biggest fixtures take place on Sunday . Liverpool play Man United at Anfield with top four place at stake . Barcelona meet Real Madrid at Nou Camp in top-of-the-table clash . Around 700m will watch Premier League encounter around the world . Real Madrid lead the revenue charts with wealth of £459.5m . Both they and Man United sell 1.5m replica shirts each year . Real have won the most trophies and have most Twitter followers . READ : Two fans take part in Q & A ahead of Sunday 's El Clasico showdown .