For my grandson, it was a great shock to find out the truth: that he was adopted by a military family, that his real mother had been killed

Rosa Roisinblit

Human rights organisations say more than 30,000 people were killed during the dictatorship.

Different events will be held across the country in memory of the victims of the Dirty War, including a march from Congress to the central Plaza de Mayo.

The Mothers of the Plaza de Mayo - mothers of those killed during Argentina's years of military rule - have held similar demonstrations every week for more than 20 years.

The 1976 coup marked the start of the dirty war

Their demand: Truth and justice. Most are now in their 70s or 80s. They are the last campaigners of their generation.

They are joined in the human rights movement by another group, the Grandmothers of the Plaza de Mayo.

The Grandmothers have one aim: to find their missing grandchildren.

Coming to terms

Many have stories like Rosa Roisinblit's. Her daughter Patricia was kidnapped in 1978. Patricia was eight months pregnant at the time.

She was never seen alive again.

For 22 years Rosa tried to track down her grandson. Last year, following an anonymous tip-off, she found him.

Seventy missing grandchildren have been found so far

"For my grandson, it was a great shock to find out the truth: that he was adopted by a military family, that his real mother had been killed.

"Now he's having to come to terms with it, it's very difficult for him."

Rosa's grandson is one of 70 missing grandchildren who have now been found. The Grandmothers are looking for hundreds more.

They and other campaigners are looking to put those responsible for human rights abuses during the dictatorship on trial.

So far two amnesty laws have prevented any trials from going ahead. But that may now change.

The country's courts have now begun to ignore the amnesty laws.

Justice possible

For campaigners like Horacio Verbitsky it is a sign of a new era in Argentina.

The Mothers want the perpetrators of abuses to be tried

"I believe that justice is possible in Argentina. It is not an easy task but there is a strong social support for justice to be done," says.

"We are very confident that new trials will succeed and that those responsible for the worst crimes against humanity will be punished."

On the eve of the anniversary, a concert was held in memory of those killed during the dictatorship.

Thousands of people gathered in a stadium in the rain.

Photos of those who disappeared were flashed onto a giant screen.

The audience was mostly young. Many weren't even born when the coup took place. But some have joined the human rights movement.

In the next few years those under the rain in the stadium may find themselves taking over the campaign from the last of the Mothers and the Grandmothers of the Plaza de Mayo.