An Istanbul court began hearing the case against the twenty-six defendants on Thursday, who are accused of founding a crime syndicate, violating public order and organizing illegal protests through social media.

The defendants, who include doctors, architects and engineers, face up to 29 years in prison for their part in the Gezi demonstrations last year that marked the biggest challenge yet to Prime Minister Recep Tayyip Erdogan's 11-year rule. They are all alleged members of the organization "Taksim Solidarity," an umbrella organization of the protest movement.

Last year's protests, which peaked in late May and June, started as a small environmentalist movement against the redevelopment of Istanbul's Gezi Park. The protests quickly blew into wider nationwide demonstrations against Erdogan's authoritarian style. Taksim Square, which lies adjacent to the park, became a key rallying point for Istanbul protesters. In the heavy-handed police crackdown that followed, at least eight people were killed and thousands more injured.

During last month's one year anniversary of the protests police used tear gas and water cannons against hundreds of demonstrators who had gathered on the streets leading to Taksim Square (pictured above).

Rights groups like Amnesty International and Human Rights Watch have called on the Turkish government to drop the charges. They say the state has wasted resources prosecuting protesters while failing to crack down on abuses by police.

hc/slk (Reuters, AFP, AP, dpa)