The Arab Spring: A timeline

On January 25, thousands of Egyptians marched in Cairo, Alexandria and other cities

From the fall of old, authoritarian leaders to the repression of revolts, here are some key dates that make up what is known as the Arab Spring.

On December 17, 2010, a young Tunisian who sold vegetables from a barrow sets himself on fire to protest police harassment.

Mohamed Bouazizi dies on January 4, 2011, but not before his gesture goes viral, sparking protests against the cost of living and the country's authoritarian president, Zine El Abidine Ben Ali.

Ben Ali's 23-year rule ends 10 days later when he flees to Saudi Arabia, becoming the first leader of an Arab nation to be pushed out by popular protest.

The spirit of the "Jasmine Revolution" soon spreads.

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On January 25, thousands of Egyptians march in Cairo, Alexandria and other cities, demanding the departure of President Hosni Mubarak -- who has been in power for 30 years -- and "bread, freedom and dignity".

On February 11, as more than a million take to the streets, Mubarak resigns and hands control to the military.

Thousands mass in Tahrir (Liberation) Square in Cairo, chanting, "The people demand the removal of the regime."

On February 15, protesters take over Pearl Square roundabout in the capital which they rename "Tahrir Square", and demand a constitutional monarchy and other reforms.

But their camp is stormed by riot police three days later, leaving three dead and scores wounded.

Troops from neighbouring Saudi Arabia and other Gulf states enter Bahrain in March 2011 to help crush protests and crack down on dissent.

The same day the Bahrain protests start, Libyan police use force to break up a sit-in against the government in the second city, Benghazi.

Clashes follow.

The country's leader Moamer Kadhafi vows to hunt down the "rats" opposing him "street by street, alley by alley, house by house".

The uprising turns into civil war with French, British and US air forces intervening against Kadhafi.

On March 6, a dozen teenagers tag the wall of their school in southern Syria with "Your turn, doctor," referring to President Bashar al-Assad, a trained ophthalmologist.

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The torture of the youths sparks mainly peaceful protests at first, and calls for democratic reform.

But with violent repression by the government, the revolt turns into civil war.

On October 20, Moamer Kadhafi is captured and killed in his home region of Sirte by rebels who find him hiding in a storm drain.

On October 23, Tunisians stream to the polls for their first free election, in which members of the Islamist Ennahdha movement triumph.

On February 27, 2012, Ali Abdullah Saleh, who had ruled Yemen for 33 years, hands power to his deputy Abdrabuh Mansur Hadi, after a year of protests.

He is the fourth leader to be undone by the Arab Spring -- this time through a negotiated transition under pressure from Gulf monarchies.

On June 29, 2014, the Islamic State group (IS) proclaims a "caliphate" over territory it has seized in Syria and Iraq.

Jihadists carry out beheadings, mass executions, abductions, rape and ethnic cleansing of minorities.

Russia, who with Iran is Assad's biggest ally, starts air strikes against Syrian rebels on September 30, 2015, changing the course of the war.

After a decade of fighting which left 380,000 dead, Assad is able to claim decisive victories.