1. Cristiano Ronaldo - £80m | Manchester United to Real Madrid in 2009
No prizes for guessing the current record holder for the world's biggest transfer.
Once again, Real Madrid smashed their own record to bring CR7 to Madrid, and the Portuguese winger has been worth every penny.
With Barcelona dominating on all fronts in Spain, Madrid wanted to make waves - and the signing of Ronaldo certainly did that.
Unfortunately for Madrid however, some lad called Lionel something has done a pretty good job of wrestling the limelight back to Barca in recent years…