Kyle Walker and Leonardo Bonucci have become two of the most expensive defenders in world football after completing their moves to Manchester City and AC Milan respectively.
City have now paid four of the top 10 fees for defenders in football history, while only three of the most expensive defenders moved to clubs outside of the cash-rich Premier League.
Here, we document the 10 most expensive defenders ever - were they worth the money?
DAVID LUIZ - Chelsea to PSG, £50m
Walker's fee does not quite eclipse the whopping £50million Paris Saint-Germain paid to sign Brazil international Luiz from Chelsea in 2014. Luiz won the Ligue 1 title in both of his seasons at PSG and he made it three in a row after he returned to Chelsea for £34m in a surprise move in August 2016, claiming his first Premier League winners' medal.
KYLE WALKER - Tottenham to Manchester City, £50m
When Walker joined Spurs from hometown club Sheffield United for £5m in 2009, few would have guessed he would one day become the most expensive English player ever. A deal worth a reported initial £45m plus add-ons means Walker - who has never won a trophy in his career - has a massive price tag to live up to at the Etihad Stadium.
JOHN STONES - Everton to Manchester City, £47.5m
City have shown a willingness to pay massive amounts for English talent, with Stones having joined the club from Everton last year. But the 23-year-old had a difficult first year as Pep Guardiola's side under-performed, conceding far too many sloppy goals as they finished third in the table. Stones' potential should still see him develop into a top talent, however.
LEONARDO BONUCCI - Juventus to AC Milan, £35.2m
A row with Juve head coach Massimiliano Allegri saw Bonucci allowed to join Serie A rivals AC Milan, who have been splashing the cash in a bid to return to the Champions League. Bonucci has won six Serie A titles at Juventus, but he twice lost in the Champions League final. Signing the Italy international - a reported target for Chelsea - constitutes a massive coup for Milan.
SHKODRAN MUSTAFI - Valencia to Arsenal, £35m
Arsenal are not normally known for their big spending, with Arsene Wenger one of world football's more parsimonious managers, but they forked out £35m to sign Mustafi from Valencia in August 2016. The Germany international had a solid first campaign at Emirates Stadium but the Gunners missed out on Champions League qualification for the first time since 1997.
ANTONIO RUDIGER - Roma to Chelsea, £34m
With club icon John Terry having left Stamford Bridge, Chelsea were in need of a new defensive lynchpin and they have turned to Mustafi's international colleague Rudiger, who joins from Roma. The 24-year arrives in London fresh from Germany's success at the Confederations Cup.
THIAGO SILVA - Milan to PSG, £33m
PSG's second entry is their current club captain, Thiago Silva, with the Brazilian having been a major success since joining in 2012. Although PSG were unceremoniously overhauled by Monaco to end their dominance of Ligue 1 last season, the 32-year-old has won four league titles and three Coupes de France in Paris.
ELIAQUIM MANGALA - Porto to Manchester City, £32m
A huge flop, Mangala's fee of £32m to join City from Porto looked overpriced enough after he was allowed to join Valencia on loan. But subsequent leaked documents suggested the total cost of Mangala's move rose to £42m as City had to buy out third party owners. Mangala is expected to be allowed to leave by Pep Guardiola, having made 48 Premier League appearances for the club.
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NICOLAS OTAMENDI - Valencia to Manchester City, £31.5m
Faring slightly better than Mangala, Otamendi has also struggled to justify a large price tag after two seasons in the Premier League. City could name a back five that has cost the club in the region of £200m if Otamendi was to partner Mangala with England internationals Walker and Stones also included in front of new goalkeeper Ederson.
ERIC BAILLY - Villarreal to Manchester United, £30m
After a strong first season at Old Trafford, Ivory Coast international Bailly has looked like a bargain compared to some of these defenders. Bailly claimed three trophies in his maiden campaign in England as Jose Mourinho led United back into the Champions League by beating Ajax in the Europa League final.
(*Prices are as reported at the time of transfers being completed.)