Thirty-three serving and retired Turkish military officers have gone on trial on charges of plotting against the elected government.
They have been arrested since last November on suspicion of conspiring to stir up anger against the government and trigger a military coup.
This is one of several trials involving accusations of anti-government plots by the military and secular establishment.
So far, more than 200 people have been detained and brought before the courts.
Yet, three years after the first official investigation, no-one has been convicted.
The investigation has strained relations between the governing AK Party, which has Islamist roots, and the secularist military.
In this latest trial, 33 naval officers are charged with involvement in a plan called Operation Cage.
The defendants were arrested after a document outlining an alleged conspiracy to attack ethnic and religious minorities was found in the home of one officer last November.
The indictment also says they intended to detonate a bomb at a popular Istanbul museum, as part of a campaign to discredit the elected government.
Turkey's military has overthrown or forced the resignation of four governments since 1960, most recently in 1997. However, the current head of the armed forces has insisted that coups are a thing of the past.
Prosecutors say they will try to link the defendants with the murders of a Catholic priest, three Protestant missionaries and an Armenian journalist.
The journalist, Hrant Dink, was shot dead outside his office in Istanbul in January 2007.
The indictments run to thousands of pages and make baffling reading, says the BBC's Jonathan Head in Istanbul.
No wonder people are confused, he adds.
Until recently, putting military officers on trial in civilian courts would have been unthinkable in Turkey.
That senior commanders have accepted these indictments with only minimal protest is interpreted by many Turks as a sign of the military's waning power.
But it is still difficult to gauge how much truth lies in the multiple plots now being laid at its door, our correspondent says.