England's performance in Australia has been really awesome. They did not just win an Ashes series here for the first time in 24 years, they became the first team ever to consign Australia to three innings defeats in a home series.
The celebrations in Melbourne were big - and there were more people there too - but the scenes in Sydney were unprecedented. It was an astonishing moment for all the England fans to witness when Andrew Strauss held up the little urn.
When you see the England captain jumping up and down on the podium with all the ticker-tape blowing around what they achieved out here finally sinks in.
Andrew Strauss and son Luca soak up the occasion in Sydney
And they had to come back from two crisis moments to do it, on the third evening in Brisbane when it looked like they would lose the first Test, and then in Perth, where they were heavily beaten. It was a serious achievement.
For the last few days in Sydney, Australia have looked like a beaten side. They have gone. We have seen England be that way before, but this is a different England, who have played some ruthless cricket.
There has been tremendous concentration in the batting, superb application in the field, with run-outs and catching that put them and Australia miles apart.
As for the bowling, the reverse swing in the last two games, led by James Anderson, has shown Australia where Test cricket has moved to.
The Aussies will not thank me for saying this, but they needed a beating like this to look at their game from top to bottom, and put some plans in place to address their problems. England have had to do exactly the same in the past.
Australia must look at the structure from top to bottom and establish what the best role is for Greg Chappell [the national talent manager]. Decisions have to be made over whether coach Tim Nielsen and chairman of selectors Andrew Hilditch keep their roles, and there is the issue over the captaincy too.
It is a strange decision by Michael Clarke to resign from Twenty20s just when he has the opportunity to stake a claim for the captaincy across all three formats.
Australia have been muddled from the start, ever since I arrived on 1 November. All the focus was on the home team from start to finish. The debate about the make-up of the Australian side was never satisfactorily resolved.
Two England players have produced some remarkable statistics: Alastair Cook hit 766 runs, the second best aggregate by any Englishman in any series, and James Anderson's 24 wickets were the best haul achieved in Australia by an English bowler since Frank Tyson in the 1950s.
Let's be clear: these are not passing stats that only interest geeks, these are massive performances.
With Anderson, we always wondered whether he would perform, whether he would get the ball to swing. The results were outstanding: orthodox swing in Adelaide, reverse swing in Melbourne and Sydney, all three of those Tests won by England.
I promised to do the sprinkler dance on the SCG outfield if we won the Ashes, and it was a promise I had to keep
England prepare the ball for swing so well, getting it to reverse after just 10 overs, earlier than any other team.
Chris Tremlett and Tim Bresnan have been given opportunities and done well, but Anderson has always been the attack leader. He has been very hostile and aggressive and has got under the skin of the batsmen.
When nothing is happening, the England bowlers are very good at building up pressure and containing the opposition batsmen with carefully set fields. It's something the Australians would do well to replicate.
Six months ago, Cook's technique was all wrong. The bat was coming down at the wrong angle, there was no footwork and his head was moving too far towards the off-stump.
Now he is a transformed player, standing up tall, driving through the covers, and cutting the ball so effectively.
Aggers fulfils sprinkler dance promise
As the vice-captain it was important for him to lay to rest the ghosts and ghouls of last summer, and he is a delightful fellow too.
My prediction before the series was a 3-1 win to England, and I was pleased to get that right. The England players gave us all what we wanted to see, and it's been noticeable how incredibly relaxed, friendly and happy they have appeared from start to finish.
I expect them to go well in the World Cup and they could win it. I'm not saying they will win it but they are definitely capable of doing so.
Winning the World Twenty20 and the Ashes within a year suggests they have the right tools in place to be a big force in the subcontinent.
I promised to do the sprinkler dance on the SCG outfield if we won the Ashes, and it was a promise I had to keep. It wasn't at the end where the Barmy Army were, I was in front of the members. Maybe that was more appropriate, in a way.
Jonathan Agnew was taking to BBC Sport's Oliver Brett
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TMS podcast: Jonathan Agnew and Geoff Boycott's review (available worldwide)