A court in Argentina has begun hearings in the largest trial of crimes committed during the so-called "Dirty War" between 1976 and 1983.
Sixty-eight former officials face 800 charges of kidnap, torture and murder associated with an elite naval college.
Among the defendants are Alfredo Astiz, known as the Blond Angel of Death, and eight former "death flight" pilots.
Tens of thousands of Argentines were kidnapped and killed by the military junta during their years in power.
The deadliest of the regime's secret detention camps was the Naval School of Mechanics (Esma) in the capital, Buenos Aires.
Five thousand people were sent to the grandiose three-storey stone building in an upmarket northern suburb.
Very few survived their time in cells in the basement and attic. The bodies of many have never been recovered.
Some were allegedly burnt and their remains disposed of.
Others were drugged and dropped from planes flying over the Atlantic Ocean.
For the first time in Argentina, the pilots of those "death flights" are on trial, among them former naval lieutenant Julio Poch, who was extradited to Argentina from Spain in 2010 after allegedly confessing to the part he played to colleagues at the Dutch airline Transavia.
Another defendant, former naval captain Emir Sisul Hess, allegedly told relatives of the dead how sleeping victims "fell like little ants" from his plane.
The trial is part of a continuing series of actions against Argentine officers and other officials associated with the military dictatorship.
Legal action began once democracy returned to Argentina in 1983, but President Raul Alfonsin brought an end to the trials in 1986, arguing the country needed to look to the future and not the past.
Three laws granting amnesty for crimes committed during the Dirty War were passed in 1986 and 1987. These were overturned in 2003.
Since then a number of high-profile figures from the regime have been convicted, including the de facto presidents Jorge Videla and Reynaldo Bignone.
Gen Videla had already been convicted of homicide, torture and kidnap amongst other crimes in 1985, but he was given an amnesty by President Carlos Menem in 1990.
About 250 convictions have been secured, including Alfredo Astiz, who last year was given a life sentence for the part he played in infiltrating left-wing groups and betraying their members to the regime.
A number of Esma officials have already been tried but human rights lawyer Rodolfo Yanzon told the Associated Press: "This was, is and will be the largest trial of crimes against humanity.
"There are 68 defendants charged in 800 cases, and we estimate there will be some 900 witnesses,"
Among the witnesses will be Graciela Palacio Lois, whose husband Ricardo never returned from a meeting of the Peronist University Youth movement in 1976.
She says she is nervous about giving evidence.
"It's one thing looking at them from the other side of the glass in the viewing gallery. But it's another thing sitting in the witness area with them in front of you."
The trial is expected to last two years.