On Tuesday, the curtain came down around Europe on one of the most memorable transfer windows in years.
A host of major names have moved on to pastures new this summer, including two of the very biggest in world football.
Significant moves don't always come with significant transfer fees, though, as Paris Saint-Germain have proved over the last few months.
The Ligue 1 giants recruited the likes of Gianluigi Donnarumma, Georginio Wijnaldum, Sergio Ramos and, most notably, Lionel Messi - all without paying a penny to their former clubs.
Messi's fellow multiple-time Ballon d'Or winner, Cristiano Ronaldo, also switched clubs this summer. The Portuguese icon left Juventus to return to former club Manchester United after a 12-year absence. Despite his legendary status, 36-year-old Ronaldo departed Turin for an upfront payment of just £13.5m from the Red Devils.
While there have were plenty of bargains to be had, a fair amount of cash was also splashed out.
Here, per Transfermarkt, are the top 40 most expensive transfers of the 2021 summer transfer window...
40. Takehiro Tomiyasu (Arsenal - £16.74m)
39. Josko Gvardiol (RB Leipzig - £16.92m)
38. Matteo Politano (SSC Napoli - £17.1m)
37. Jhon Cordoba (Krasnodar - £18m)
36. Juan Musso (Atalanta - £18m)
35. Boubakary Soumare (Leicester - £18m)
34. Weston McKennie (Juventus - £18.45m)
33. Odilon Kossounou (Bayer Leverkusen - £20.7m)
32. Enock Mwepu (Brighton - £20.7m)
31. Andre Silva (RB Leipzig - £20.7m)
30. Marc Guehi (Crystal Palace - £21m)
29. Arnaut Danjuma (Villarreal - £21.15m)
28. Nicolas Gonzalez (Fiorentina - £21.15m)
27. Emerson Royal (Tottenham - £22.5m)
26. Gerson (Marseille - £22.5m)
25. Bryan Gil (Tottenham - £22.5m)
24. Aaron Ramsdale (Arsenal - £25.2m)
23. Daniel James (Leeds - £26.19m)
22. Fikayo Tomori (Milan - £26.28m)
21. Joe Willock (Newcastle (£26.48m)
20. Danny Ings (Aston Villa - £26.48m)
19. Nikola Vlasic (West Ham - £27m)
18. Matheus Cunha (Atletico Madrid - £27m)
17. Donyell Malen (Borussia Dortmund - £27m)
16. Patson Daka (Leicester - £27m)
15. Eduardo Camavinga (Real Madrid - £27.9m)
14. Leon Bailey (Aston Villa - £28.8m)
13. Kurt Zouma (West Ham - £31.5m)
12. Rodrigo de Paul (Atletico Madrid - £31.5m)
11. Martin Odegaard (Arsenal - £31.5m)
10. Emi Buendia (Aston Villa - £34.56m)
The Argentine midfielder may have missed out on his country's Copa America triumph over the summer but did manage to secure a big-money switch from Norwich to Villa Park. The 24-year-old looks set to play a major role for Dean Smith's men this season.
9. Tammy Abraham (Roma - £36m)
The 23-year-old struggled for game time at Chelsea last year. It doesn't like that with be an issue for Abraham in Rome under Jose Mourinho. The Englishman received a standing ovation from his new side's supporters following his Serie A debut last month - and the move looks to be suiting him well.
8. Ibrahima Konate (Liverpool - £36m)
Liverpool's only major signing of the window, the 22-year-old French U21 international could prove to be a bargain for the Reds if he fulfils his considerable potential in the coming years.
7. Raphael Varane (Manchester United - £36m)
One of a trio of huge deals landed by the Red Devils this summer, French World Cup winner Varane is a major addition to United back-line. The former Real Madrid man has won pretty much everything there is to win in the game and fans will be hoping that Varane lifts plenty more silverware at Old Trafford.
6. Dayot Upamecano (Bayern Munich - £38.25m)
Upamecano joined the six-time European champions this summer, having previously established himself as one of the best centre-backs in the Bundesliga at RB Leipzig.
5. Ben White (Arsenal - £52.65m)
The biggest purchase of a busy transfer window for the Gunners, White has starred at the heart of defence for Leeds - and then Brighton - over the past couple of seasons. The north London side dug deep to land the 23-year-old and will be hoping that he can quickly justify their considerable outlay.
4. Achraf Hakimi (PSG - £54m)
PSG may have done some fantastic business in terms of free transfers, but they also parted with a significant sum to land Inter Milan right-back Hakimi. The Morrocan international will be surrounded by some of best players on the planet as the Parisian club hunt success both domestically and in Europe.
3. Jadon Sancho (Manchester United - £76.5m)
Ole Gunnar Solskjaer finally landed his man this summer, ending a long-term pursuit of the England winger from Borussia Dortmund. The 21-year-old joins a midfield roster stacked with talent at Old Trafford this season.
2. Romelu Lukaku (Chelsea - £103.5m)
The Blues forked out a nine-figure sum to land the powerhouse Belgian forward for a second time, having allowed him to depart the club initially in 2014. It's a considerable fee, but the 28-year-old has already begun to repay it, notching his first-ever goal for Thomas Tuchel's men against Arsenal recently.
1. Jack Grealish (Manchester City - £105.75m)
Aston Villa didn't want to lose their prized asset at any cost, but when City met Grealish's £100m-plus contractual release clause, their hands were tied. A British transfer-record, the England playmaker is now part of an insanely strong midfield at the Etihad Stadium.