Many players reach star status after big-money moves from one club to another. But here are the best who came up through their club system to become elite players.
10) Gianluigi Donnarumma - AC Milan
Have a guess how old Donnarumma is. He made his first-team debut for Milan in 2015, almost instantly becoming a regular, so that might help you out. Is he 24, 25? Maybe 26 then. Wrong: he's still only 21, just old enough to hire a car but for some time a man whom Milan have looked towards during troubled times.
And, in the past five years, there have been plenty of troubled times. It has not all been peaches and cream for Donnarumma at Milan (having Mino Raiola as your agent will see to that), but the man who made his debut as a boy is still there, and if the glory years are to return then it would seem fitting if he were there to see them. However, he is constantly linked with a move away from the club.
9) Hector Bellerin - Arsenal
Hearing Bellerin speak can be a slightly strange experience, his accent pitched somewhere between Catalonia and the streets of Islington.
Bellerin has been at Arsenal since age 16, and he has now cemented his status as one of the most important players at the club.
Bellerin is a leader, not just through the usual sort of chest-thumping and ear-bashing ways we expect of captains in England, but through example: a smart, socially conscious, responsible footballer. Arsenal fans should be proud of having him as one of their own.
It takes a pretty exceptional level of talent and determination to break into a team that just buys and buys. Having the sort of money PSG do, the expectation is that success must be instant, and the pursuit of instant success doesn't often lend itself to patiently nurturing youngsters.
Kimpembe joined the youth ranks at PSG as a 10-year-old, and while in truth his performances have been up and down since he broke into the first team a few years ago, he has looked like fulfilling his promise this season. His performance against Borussia Dortmund just before the coronavirus-enforced lockdown in particular was exceptional, and he more than most may have cursed the suspension of football.
It's easy to forget that Rashford sort of broke onto the Manchester United first team by accident. It was only an injury crisis that meant this skinny, slightly gawky striker got his chance for Louis van Gaal's side, given a debut against Midtjylland in the Europa League, but he took it with gusto. He scored twice in that game and twice more against Arsenal in the Premier League a few days later, and at times it feels as if he has been holding United together almost on his own ever since.
6) Koke - Atletico Madrid
A lot has changed at Atletico Madrid over the past few years. The likes of Diego Godin and Gabi have gone from the Diego Simeone glory years, when they won La Liga and reached two Champions League finals with that physical, rapacious style of football.
Things are different now, but the 28-year-old midfield sensation could have left Atletico any number of times but stayed at "the club of my life."
Relations between their longest-serving player and the Atletico fans have started to fray a little this season, but when the great histories of the Simeone era are written, Koke, who joined the club aged 8 and has seen no reason to leave, will be one of its biggest characters.
5) Sergio Busquets - Barcelona
It probably would have taken something going quite seriously wrong for Busquets not to end up as part of the Barcelona furniture. His father Carles was a dutiful Barca stalwart, a backup goalkeeper for most of his decade with the first team, but a stalwart nonetheless.
Along with Pedro, Busquets was one of a couple of players who were not tipped for big things as a youngster, but whom former Barca coach Pep Guardiola plucked from the B team when he took over in 2008 and turned into a lynchpin of not only Barca but Spain too.
Much like Busquets, Kane was not a player picked out for stardom from a tender age. Before he broke through at Tottenham, he spent some pretty undistinguished loan spells at Leicester, Norwich, Millwall and Leyton Orient, and anyone who watched him then would not tell you this was a future World Cup Golden Boot winner.
But more or less from the moment he did get himself into the Spurs team, he hasn't stopped scoring, closing in on 200 career goals now, and he's only 26.
It's easy to forget Alexander-Arnold is still only 21, a youngster who seems to have been around for years at Liverpool. It isn't really much of a surprise that he feels like part of the furniture, because he is one of those players who just looked like he belonged straight away.
While the most important thing about Alexander-Arnold is his ability as a player, it helps that he's a local lad, from West Derby, a suburb just a mile or two from Anfield. In Liverpool's 1970s and '80s heyday, there would usually be two or three Scousers in the team, but while this side is a much more international bunch, they do have Alexander-Arnold.
For a player whose best qualities haven't always immediately been obvious, Muller's rise was pretty meteoric. At the start of the 2009-10 season he'd made only four senior appearances for Bayern Munich, and by the following summer he had jointly won the World Cup Golden Boot, then was shortlisted for the Ballon d'Or a few months later.
Some of Bayern's greatest players have been homegrown, from Franz Beckenbauer to Phillip Lahm to Uli Hoeness, and although Muller's status might be a little uncertain these days, he definitely belongs in that company.
1) Lionel Messi - Barcelona
In 2000, a tiny 13-year-old boy arrived for a trial at Barcelona and changed the course of football history forever. Two decades later, he's still the greatest player in the world, perhaps the greatest of all time, and a man around whom one of the greatest club teams we've ever seen has been built.
Recent years have seen suggestions that Messi is too powerful, that no one single player -- no matter how good -- should have so much influence on a club, but if anyone does justify it, Messi does. In a few years, he'll be gone. What will Barcelona do then? What will any of us do then?