Tehran - First Iran and the five UN Security Council permanent members plus Germany meet in Geneva and resume nuclear negotiations after more than a year of stalemate. That meeting even sees Iran and US representatives chatting over lunch after more than 30 years of diplomatic freeze.
Then the International Atomic Energy Agency's head, Mohamed ElBaradei, comes to Tehran and negotiates, for October 25, the first IAEA inspection of the nuclear enrichment plant Iran now says it has near the holy city of Qom.
Negotiations are also arranged with France and Russia - to be held on October 19 - on Iran sending low-grade enriched uranium to those two countries for further enrichment.
At the end of just 96 hours, everyone is beaming about the results of negotiations which for years have shown no progress.
"We are in a critical moment, but I believe that we are on the right track for building the required confidence," says ElBaradei.
As far as Iran's President Mahmoud Ahmadinejad is concerned, the nuclear dispute has already been resolved, "because there are no more ambiguities".
The Western media have been writing that Iran will be sending "a major part" of its uranium abroad for enriching.
The jubilant Iranian media have been saying that Iran has at last got its way with the world powers, and that its nuclear programme is recognised by them.
"It looks as though all - in particular Iran and the US - have been yearning for a breakthrough, even though what's been achieved so far is at most a positive moment in the process - and no way a breakthrough," says one diplomat in Tehran.
Indeed, Iran in fact negotiated both subjects - inspecting the newly-revealed enrichment plant near Qom and sending uranium abroad - with the IAEA before the Geneva negotiations.
Furthermore, Iran never did rule out sending its uranium abroad for enrichment, and said that it would also be acceptable for it to buy its enriched uranium.
What Iran always insisted was not up for negotiation was its right also to enrich its own uranium - something on which Iran "is still insisting", says Iranian chief negotiator Saeed Jalili.
Uranium enrichment inside Iran - which Tehran says has never exceeded five per cent enrichment, and thus is suitable only for generating energy and not for producing nuclear weapons - was the core issue in the confrontation between Iran and the West.
The US, Israel and the European Union fear that Iran will not stick to the five per cent level, and could be working on a nuclear bomb.
Inspecting the newly-revealed plant near Qom would have gone ahead sooner or later anyway, even without the negotiations in Geneva, observers say.
The head of Iran's nuclear organisation Ali-Akbar Salehi says the visit by ElBaradei and the IAEA inspections that come from it have nothing to do with the negotiations that went on in Geneva.
And another Tehran diplomat observes that Iran "will have definitely won" should there be agreement that the IAEA inspection and sending uranium abroad for enrichment are an acceptable solution.
There are still outstanding issue - including the precise amount of low-grade enriched uranium Iran will be offering for further enrichment abroad when negotiations start in Vienna on October 19.
"We need rational decisions so that the status quo improves," ElBaradei told Ahmadinejad in Tehran. The IAEA head never was keen on increased sanctions or military threats against Iran.
What he demands of Iran is that it allows the IAEA to carry out tougher inspections. That, he says, could help bring to an end the confrontation with the Western nations.
Iran has so far rejected this, but has also always stressed that if sanctions are lifted, it will seriously consider allowing the more stringent inspections provided for in an IAEA additional protocol.
