"Iran is like an onion," my translator keeps telling me. "Every time you peel away a layer there is another one underneath." No kidding.

Yesterday we braved two huge campaign events — duelling rallies that brought traffic to a standstill across Tehran. Although that's not entirely unusual even on a normal day in this city of some 13 million people.

For the first, we joined the supporters of campaigning President Mahmoud Ahmadinejad as they streamed towards a huge, still unfinished mosque on the outskirts of town.

A supporter of Mahmoud Ahmadinejad holds a poster of the Iranian president from her car window. With Farsi hip-hop and techno music blaring from car speakers and young men and women dancing in the streets, election fever in Tehran is more like a party than a protest. (Ben Curtis/Associated Press)

The air was thick with exhaust from all the buses carrying in people from the country.

But the procession had the drive and enthusiasm of fans heading to a rock concert and organizers had made some rock concert-like preparations of their own.

White tents with medical staff were on hand, waiting for the first victims of heat stroke or whatever excitement might come of seeing their president in the flesh.

In the crowd, I met a thoughtful woman, a gynaecologist wearing a full chador, trying to battle her way closer to the big screens set up outside the mosque. I asked her about relations with the United States.

"It's not worth being involved in conflict and war," she told me. "We only come once to this world and we don't come to fight with each other."

As she moved off, you could better hear the warm-up acts rallying the crowds with cries of "Death to America" and "Death to Israel."

In the end, Ahmadinejad never made it to the stage. Revenge of the traffic? At least that was the rumour, an ironic one at that given the former mayor of Tehran is reported to have a PhD in traffic management.

A human chain

The second big event was the "human chain" formed by the green-clad supporters of self-styled reform candidate Mir Hossein Mousavi.

It was a universe away and I don't mean just because of the traffic.

The Mousavi campaign is full of young people tuned in to the outside world through the internet in a way their parents aren't. Though many seem to be dragging their parents along for the ride.

Many Iranians won't thank you for implying that something happening in the United States these days might be having an impact here. Persia, after all, was one of the world's great civilizations.

A campaign rally for the main reformist candidate, Mir Hossein Mousavi, at the Heidarnia stadium in Tehran on Tuesday, June 9, 2009. (Ben Curtis/Associated Press)

But a young Mousavi supporter I met told me the Mousavi campaign is bringing hope to Iran in the same way Barack Obama brought it to the U.S.

Maybe, but I have some trouble with that notion.

For one, how is it that these jolly green campaigners, who've managed to turn a dull election into a throbbing, pulsating horse race, with street scenes reminiscent of a Stanley Cup celebration, have come to rest their hopes on the rather dull figure of Mir Hossein Mousavi?

Until recently, many here saw him as belonging to the history books.

Who is this man?

Mousavi was no stranger to the Iranian Revolution and some of the more oppressive legislation that followed during his tenure as prime minister from 1980 to 1988.

In recent years, he's been largely out of sight, working on his art.

Even political scientist Sadegh Zibakalam finds it hard to explain this current green surge for Mousavi.

"I would have told you, yes, I'm prepared to bet you a thousand to one that Mousavi doesn't stand a chance.

"Who knows him to begin with? The man has been prime minister [but] during the past 20 years no one's heard of him."

The academic has since changed his mind. "It appears that an earthquake, a flood, an avalanche is coming that is much more powerful than the one that brought [former president Mohammed] Khatami to power.

"We are surprised, we are baffled, but it is coming."

One important factor in Mousavi's favour has been the endorsement of Khatami, who was elected in 1997 and 2001. He was going to run again this time but dropped out and put his weight behind Mousavi.

Face to the West

There's no doubt all the modern bells and whistles of Mousavi's slick election campaign is appealing to young people.

So, perhaps, is the presence of his artist wife who is breaking political taboos by campaigning alongside him at a time when many Iranian women are pushing hard for their rights.

Another side of campaigning president Mahmoud Ahmadinejad: a poster showing him paying his respects to an older man. (Kamran Jebreili/Associated Press)

But there are other factors at play as well.

At a recent art exhibition connected to the Mousavi campaign, I met an architect in her 30s named Parissa.

She was almost in tears as she spoke of how much she believes Iran has lost over the past four years, most importantly the respect of the international community.

She fears her country as a whole is being judged by the harsh image of its current leader.

A young man at the same event said almost exactly the same thing.

"We want to protect ourselves. To protect our face in front of other countries, from the bad impact we get from Mr. Ahmadinejad."

Whether by design or circumstance, Mousavi has become the main guardian of those hopes.

But they are not the only ones in this divided nation. Ahmadinejad still enjoys broad support with Iran's working poor and those who admire his uncompromising stand against the West.

Even teenage girls here make up songs like "Nuclear Man! You have broken the back of the enemy!"

One layer down. Several more to go. Iran is like an onion.