A series of deals sparked a chain reaction in 2013 that connected the top sides in Europe as players were bought and sold on in equal measure.
Take Napoli as a starting point, for example. By selling Edinson Cavani to Paris Saint-Germain for €64.5 million, [£55.5m] the Serie A side obtained the cash to strengthen their team, with Real Madrid trio Gonzalo Higuain (€37m [£31m]), Jose Callejon (€10m [£8.4m]) and Raul Albiol (€12m [£10m]) heading to the Stadio San Paolo for a combined figure of €59m [£49.5m].
The sale of that trio allowed Madrid to break the world transfer record and spend €100m [£86m] on Gareth Bale, which in turn prompted the Santiago Bernabeu side to sell Mesut Ozil to Arsenal for €50m [£42m] and offload Kaka to AC Milan for free as the duo were no longer needed.
Tottenham Hotspur had money to spend with Bale on his way to Madrid and the Premier League outfit brought in Erik Lamela from Roma for €30m [£26m] after the Giallorossi purchased Gervinho from Arsenal for €8m.
There is also a link between the transfers of Neymar, David Villa and Radamel Falcao. The Brazilian's switch to Barca saw Villa's spell at the club come to an end, while Falcao's decision to leave Atleti for Monaco saw the Vicente Calderon side in need of a new striker.
Finally, the Mario Gotze deal from Borussia Dortmund to Bayern Munich was at the centre of a string of transfers across the world.
BVB made €37m [£32m] on the creative midfielder and then spent €13m [£11m] on Pierre-Emerick Aubameyang and €27.5m [£23m] on Henrikh Mkhitaryan to strengthen their squad again. The Armenian midfielder's departure, meanwhile, allowed Shakhtar Donetsk to sign Bernard for €25m [£21m].
Furthermore, the signing of Gotze saw Bayern cash in on Mario Gomez (€15.5m [£13m]) as the prolific striker joined Fiorentina, with the Serie A team then selling Stevan Jovetic to Manchester City for €27.5m [£23m].
The Montenegro star was not the only new arrival at City as Alvaro Negredo (€28m [£23.5m]) also found his way to the Etihad Stadium, with Carlos Tevez then departing to Juventus for €11.8m [£9.9m].