Turkey's opposition leader declared a new beginning for the country and demanded reforms to the country's current government at a huge pro-democracy rally in Istanbul on Sunday.

Hundreds of thousands of demonstrators gathered in Turkey's first city following a peaceful 25-day March for Justice that began 250 miles away in the capital city of Ankara. Kemal Kilicdaroglu, the leader of the Republican People's Party (CHP), organized the march with other politicians to protest President Recep Tayyip Erdogan's authoritarian government.

Since rising to power as Turkey's prime minister in 2002, Erdogan has exhibited an increasingly dictatorial style of leadership. His Justice and Development Party (AKP) has muzzled the press and removed judges from the country's highest courts in an apparent effort to gain control over the judiciary.

"This is a rebirth for us, for our country, and our children...Justice is a right, we want our right back. We millions here demand a new social contract."—Kemal Kilicdaroglu, Republican People's Party

After a deadly coup attempt in the summer of 2016 by a faction of the Turkish military, Erdogan has accelerated his crackdown on his opponents. Tens of thousands of journalists, civil servants, and other workers have been arrested and suspended from their jobs since the coup attempt. The arrests have been condemned by the European Union, which Turkey has sought to join, and international human rights groups.

Erdogan was also granted sweeping new powers after narrowly winning a referendum in April 2017. A slim majority of Turkish voters chose to end the country’s parliamentary system, giving the president full control of the government—a move supporters said would modernize the country but which critics decried as a further step towards autocratic rule.

The protesters who gathered in Istanbul on Sunday demanded the release of those who have been unfairly detained, and the return to an independent judiciary system.

Kilicdaroglu called the anti-Erdogan rally "a revolt against injustice."

"Nobody should think this march has ended; this march is a beginning," he said to the huge crowd, which included government employees who have been suspended following the coup attempt. "This is a rebirth for us, for our country, and our children...Justice is a right, we want our right back. We millions here demand a new social contract."