Forty-seven suspects, mainly soldiers, are being tried on charges of plotting to assassinate Turkish President Recep Tayyip Erdogan during the July 15 2016 coup attempt.
The court in Turkey’s southwestern Mugla province is hearing the case with three of the suspects being tried in absentia as they remain on the run.
The suspects were led into the courthouse by security forces in front of television cameras to whistles and shouts of derision from onlookers.
Erdogan, who was holidaying at a hotel in the upmarket Aegean resort of Marmaris with his family on the night of the coup, escaped only minutes before the assassination attempt.
Later that night, Erdogan spoke on live television about how he narrowly escaped with his life when the hotel was bombed 15 minutes after he left it.
Prosecutors have sought multiple life sentences for each of the suspects, who include an alleged hit squad of 37 soldiers suspected of seeking to carry out the plan.
Turkish officials say the plot to kill Erdogan was a key part of the plan to usurp the elected government, a plot they say was masterminded by the US-based Muslim cleric Fethullah Gulen.
Two Turkish policemen who were helping to guard Erdogan at the hotel were killed, according to the indictment.
Accompanied by close family members including his son-in-law, Energy Minister Berat Albayrak, Erdogan managed to flee Marmaris and fly to Istanbul where he oversaw the suppression of the coup.