A man has gone on trial accused of planning to crash a plane into the mausoleum of modern Turkey's founder.
Metin Kaplan was held in Germany while Turkey had the death penalty
Metin Kaplan faces life in prison if he is convicted of a plot to destroy the tomb of Mustafa Kemal Ataturk during anniversary day celebrations in 1998.
Mr Kaplan, who denies the charge, was extradited from Germany in October after Turkey banned the death penalty.
He is known by supporters as the Caliph of Cologne and leads a group that wants to create an Islamic state.
His group, the Caliphate State, which wants to overthrow Turkey's secular government, was banned in Germany in 2001 as anti-democratic and unconstitutional.
The Turkish authorities claim Mr Kaplan planned to fly an airplane laden with explosives into the Ataturk mausoleum amid celebrations for the 75th anniversary of the republic, when the country's military, bureaucratic and political elite would have gathered at the site.
Mr Kaplan, 51, who has served a four-year jail term in Germany for
calling for the murder of a rival Islamic leader, is accused of an armed attempt to overturn the constitutional order.
The German authorities had long refused to send him to Turkey and yielded only after receiving assurances that he would not face the death penalty.