The prosecutor claims the defendants, many of them active in civil society, "attempted to overthrow the government" of then-Prime Minister Recep Tayyip Erdogan, through organizing and financing an "uprising." The charge carries a life sentence. Erdogan is now Turkey's president.
Protests began in 2013 to protect the small Gezi Park in central Istanbul from development but quickly transformed into wider anti-government demonstrations across Turkey. Police used tear gas and water cannons to disperse mostly peaceful protesters, leading to widespread criticism of how Turkish authorities handled the protests.
Among the 16 are Kavala, in pre-trial detention for 20 months, and Yigit Aksakoglu, who works for an early childhood education foundation, detained for eight months. In his first court appearance Monday, Kavala said there was no evidence against him to substantiate the charges that he planned an uprising. The indictment also claims that billionaire philanthropist George Soros masterminded the Gezi protests, but does not list him as a suspect.
Erdogan is among the 746 complainants on the indictment and has publicly accused Kavala of financing the protests with Soros' backing. Kavala, the founder of an organization that focuses on cultural and artistic projects for peace and dialogue, told the court his activities in civil society have been transparent and included engaging with the government.
Kavala argued, based on academic and human rights research, that the protests were varied individual and collective acts in numerous cities, without central organizing. "I'm no different than the hundreds of thousands of people who conducted peaceful activities during the Gezi events and I request my release and acquittal," he said.
Aksakoglu, the Turkey representative of Dutch philanthropic Bernard van Leer Foundation, also demanded his release, saying the charges against him were imagined. Kavala's arrest in November 2017 was internationally condemned. The European Union questioned whether the Turkish judiciary adhered to international standards after the indictment was announced in February.
The 657-page indictment cites hundreds of intercepted telephone conversations from the defendants as well as their travels abroad and social media posts. The defendants are also accused of numerous other charges, including damaging property and damaging places of worship and cemeteries.
Human Rights Watch called the charges "bogus," saying the indictment does not explain how the defendants planned an uprising. The group said the aim of the trial was to "silence and punish the defendants for their legitimate and entirely peaceful civic activities and work."
Since a failed coup in 2016, activists, journalists and opposition lawmakers have been caught up in the net of a widespread crackdown by the Turkish government that initially began against the network of a U.S.-based cleric accused of masterminding the attempted overthrow.
David Diaz-Jogeix, senior director of programs at freedom of expression organization Article 19, said in a statement Monday: "The indictment attempts to link the 2013 Gezi Park protests to the 2016 coup attempt, despite a lack of tangible evidence. The Turkish Government is trying to rewrite history as a pretext for closing down civil society voices that challenge its authoritarian rule."
Previous trials on the Gezi protests resulted in the acquittal of defendants on the basis of freedom of assembly. Six of the defendants, including journalist Can Dundar and actor Memet Ali Alabora, are abroad.
The trial is taking place in a prison complex on Istanbul's outskirts.