The world's 10 most expensive defenders
Manchester City have signed defender John Stones from Everton for £47.5million, making him the second most expensive defender in football history.
The 22-year-old England international has signed a six-year contract.
Here the Press Association looks at the 10 most expensive defenders in the world.
1. David Luiz
Brazil international Luiz became the most expensive defender in 2014 when he was sold by Chelsea to Paris St Germain for £50million.
2. John Stones
Stones had a mixed campaign with Everton last time out but City manager Pep Guardiola was persuaded he could be a key player at the Etihad Stadium. The initial fee is believed to be just short of the £50million mark.
3. Thiago Silva
At the age of 27, Silva joined PSG in 2012 on a five-year deal for a fee of approximately £33million, which took over a month for the two clubs to agree.
4. Eliaquim Mangala
Manchester City signed Frenchman Mangala from Porto in 2014 for a fee of £32million. According to reports, City are now prepared to sell the player, who has struggled to live up to his price-tag.
5. Nicolas Otamendi
Another big-money defensive arrival at Manchester City, Otamendi was a £31.5million from Valencia last August.
6. Rio Ferdinand
When Ferdinand was sold by Leeds to Manchester United in 2002, a new British record was set as Leeds received a fee of around £30million for the defender.
7. Mats Hummels
Neither side has revealed the fee involved, but Bayern Munich are thought to have stumped up close to £30million when signing Hummels from Borussia Dortmund this summer.
8. Dani Alves
In 2008, Alves' transfer to Barcelona from Sevilla made him the most expensive right-back in the world as Barca paid a fee equivalent at the time to £28.5million for the Brazil defender.
PSG signed Marquinhos from Roma on a five-year deal for a fee of around £27million in 2013.
10. Luke Shaw
England defender Shaw became one of the world's most expensive teenagers in 2014 when, at the age of 18, he was sold to Manchester United by Southampton for £27million.