Football has gone crazy when it comes to the transfer market. The amount of money shuttling between clubs these days is mind-boggling.PSG this season stunned the world with a record €222m transfer for Neymar - a transfer shook the world of football.A transfer deal of such dimensions immediately had major aftershocks in the transfer market. This transfer created a ripple effect which inflated player prices and saw Barcelona pay €152m for Ousmane Dembele whose quality is still up for debate.Meanwhile, Manchester City spent more than €200m just to reinvigorate their defensive line and highlights the changes in the way that clubs value defenders.Here is a look at the five most expensive defenders in the history of football.#5 John Stones: Everton to Manchester CitySeason: 2016/17Transfer fee: €55.6mManchester City bought English central defender John Stones for a whopping €55.6m from Everton. The signing by Pep Guardiola made the then 22-year-old the most expensive English player ever.Stones possesses some unique abilities for a defender which gained Pep's attention. He is one of the best passers in the Premier League as he likes to play short passes and doesn't dive into tackles.Stones' control of the ball links well with Guardiola's philosophy of playing out from the defence and his pass success rate of 95% is one of the best in the world for defenders.He is also a good attacking option from set-pieces and has three goals against his name from his four Champions League games this season.While the centre-back had an average first season at City, he has begun to show his quality by putting in solid displays this season which have contributed to City having one of the best defences in the Premier League. The former Everton man who is just 23, has the potential to become one of the best defenders in the world.