There is a strange-looking building alongside the headquarters of the Iranian Atomic Energy Organisation, in its spacious compound in north-central Tehran.
It looks like an early attempt at a modernistic mosque. There is a big, rather flat dome, with a tall, square column sticking up beside it, that could be a minaret.
But this is, in fact, the Tehran Nuclear Research Reactor - and there is nothing particularly secret about it.
Many Iranians feel the West's policy is hypocritical
In fact, I was allowed to film there several times, though we had to make sure the call to prayer was not going on at the time, otherwise people would have thought it really was a mosque.
The reactor was the first foundation-stone in Iran's nuclear programme. It was constructed back in the 1950s.
By now, you have probably guessed who built it. That is right - the Americans. They even gave the Iranians some highly-enriched uranium to experiment with as well.
Of course, things were very different then. Iran was ruled by the Shah, and the Islamic revolution was still in the distant future.
Iran's government is sticking to its guns over its nuclear ambitions
The point is that there is so much geopolitics and hype surrounding the Iranian nuclear issue, that it is hard to get an objective perspective on it.
It is of course the Americans who are now prodding the campaign to pressure the Iranians into giving up their nuclear ambitions. The US and Iran have been bitterly at odds since the Iranian revolution in 1979 and the hostage-taking at the US embassy in Tehran.
Today, American forces practically encircle Iran. They are on warships in the Gulf, in bases on its Arab side, and all over the place in neighbouring Afghanistan to the east, and Iraq to the west.
Hard-liners in Washington clearly hope, that after the Taleban and Saddam Hussein, the Islamic regime in Tehran will be next to go.
So it is not surprising that they should seize the nuclear issue as a stick with which to beat Iran - and equally unsurprising that Tehran should see the mounting international pressure as an American-orchestrated campaign to force an independent nation into submission.
That is an argument that goes down well with many ordinary Iranians, including some who are not fans of the Islamic regime. It is hard for them not to agree that there is a double standard at play.
Everybody knows, they say, that America's closest regional ally Israel, has basements full of nuclear weapons, but nobody says a word about it. Nearby Pakistan and India both have the bomb too. So why not us?
The authorities, of course, insist that they are not after nuclear arms, just peaceful power. But there is a nationalist streak in most Iranians.
Hostility to the US has been high since the days of the hostage crisis
Many would be proud if they did join the nuclear club, and assume that is what their leaders are trying to do, though some would not want the bombs to be in the hands of the current regime.
Whether the West likes it or not, it has become an issue of national pride, which is why there is not much audible dissent across the normally fractious political spectrum.
But that is not to say that there no different approaches. Until late 2003, it looked as though the nuclear issue might just act as a bridge to draw Iran out of its isolation.
While insisting on their right in principle to develop their own nuclear fuel, a combination of reformists and pragmatic conservatives agreed with Britain, France and Germany to suspend Iran's enrichment activities.
At one moment, it even looked as though Tehran had driven a considerable wedge between the three big European powers, and the US.
But then two years ago came a lurch towards the hard line, when the conservatives won general elections, and then took the presidency last year.
The detente fostered by former President Mohammad Khatami has gone down the drain, along with the goodwill of men like British Foreign Secretary Jack Straw, who made more trips to Tehran than to anywhere else. The European carrot has become a stick.
At the moment, it looks as though Iran has gone into reverse, on a course that may lead to greater isolation and diplomatic and economic pressures.
It is not yet certain that it will face international sanctions after referral to the UN Security Council.
It always used to slip off the hook at the last moment, though the new hardline leaders, especially the president, Mahmoud Ahmadinejad, is less inclined and less adept at that.
If it does come to the crunch, Iran will not be an easy nut to crack - especially on this issue, where there is not likely to be a big split between the regime and the people.
A few years ago, some Iranians were tempted to think that the Americans might be able to bring them a better life. But now, looking at the chaos just next door in Iraq, they have had second thoughts.
From Our Own Correspondent was broadcast on Thursday, 12 January, 2006 at 1100 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.