Everything you need to know about the revolutions which continue to shake the Middle East.
By Oliver Hotham Follow @OliverHotham
The Arab Spring was the major news story of 2011, with major protests taking place in Tunisia, Syria, Algeria, Egypt, Yemen, Iraq, Bahrain and other Middle East countries. Autocrats all over the region were brought down by demonstrators calling for democracy, human rights, and religious tolerance.
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Since then the tone has soured. The optimist idealism of the events in Tunisia and Egypt has been replaced with a more pessimistic realism. The ongoing violence in Syria is probably the most prominent example of this - the Assad regime desperately clings to power with no sign of abdicating and, according to the United Nations, 6,200 civilians have been killed by the army on the orders of the government.
It is in 2012 that the consequences of the Arab Spring for the future of the region will become clearer.
How did it begin?
Dissatisfaction with the autocracy of their rulers and economic uncertainly had been growing amongst people in the region for years. But what we refer to as the Arab Spring really started in Tunisia, with a young man called Mohamed Bouazizi who, frustrated with his unemployment, high food prices and the harassment he endured by public officials, set himself on fire in December 2010.
This act of self-sacrifice sparked an uprising in the Arab world which has brought down autocrats who had rules for decades, but has also seen brutal repression of peaceful protesters.
Country after country fell into a state of revolution.
The first major turning point was in Tunisia, as protests brought an end to the 20-year rule of Zine El Abiden Ben Ali on January 14th. Having attempted to stay in power, the insistence of the protesters that "the people want to bring down the regime" and their refusal to compromise emboldened revolutionaries across the region.
But the world really took notice with the protests against president Hosni Mubarak of Egypt, whose junta had ruled the country since the 1950s.
The government was overthrown over the course of 18 days and fell on February 11th.
The uprisings, at this point, had spread all over the region, with Yemen, Bahrain and Syria all engaged in fully-fledged revolutions against their governments.
What was the international response?
The international response was, at first, tepid, and highly dependent on the country undergoing the unrest.
Many of the autocrats being toppled were allies in the 'war on terror'. President Obama, for example, had referred to Mubarak as a "stalwart ally" and "a force for stability and good in the region".
There was also the fear that secular autocrats were a lesser evil compared to the perceived alternative – fundamentalism. In an area with a huge proportion of the world's oil, political instability is never welcomed.
But western leaders, especially after the success in Egypt, began to praise the revolutions.
David Cameron told protesters that "we are on your side". French foreign minister Alain Juppé said: "We must not be afraid of the Arab Spring because it embodies universal values - dignity, freedom, respect for human rights, the right of people to choose their own leaders."
What happened in Libya and why did Nato intervene?
The issue of western involvement in the events in the Middle East came to a head with the uprising in Libya against Muammar Muhammad Abu Minyar Gaddafi, who had ruled the country with an iron first since 1969.
Unlike in Egypt and Tunisia, Gaddafi refused to step down when an uprising took place in February, and a bloody civil war between forces loyal to the opposition Libyan Transitional Council and government loyalists began.
Faced with the Libyan government's brutal repression of protesters and bombing of civilians, the international community began calling for the dictator to stand down.
As the violence escalated, and calls for western intervention in Libya grew louder, Nato moved to enforce the United Nations security council resolution 1973. The resolution called for an 'immediate ceasefire', and permitted the international community to use 'all means necessary short of military occupation' to prevent further civilian casualties.
Nato began its military intervention in the Libyan civil war on March 19th.
The civil war continued, and became into a stalemate until August, as Gaddafi weakened and the rebels began to take city after city, capturing the capital Tripoli on the 28th.
The Libyan Transitional Council declared themselves victorious on October 23rd, three days after Gaddafi was captured and killed trying to escape the western city of Sirtre.
How have events developed in 2012?
The countries whose revolutions were successful in bringing down their dictators have held elections.
Egypt and Tunisia have held parliamentary elections and put into place new constitutions. Libya's interim government is preparing for elections.
But a great number of the protests which began in 2011 are ongoing.
The Yemeni opposition continues to protest against the government, and has been doing so for a year. In the largest protests in the country for decades, thousands of civilians have been killed and the situation has the potential to turn into a civil war between the government, the opposition, and Islamist groups.
Protests continue in Saudi Arabia, where calls for labour, women's and Shia rights have been prominent. The country is notorious for its conservative brand of Sharia and the despotic rule of its royal family.
Bahrain is also still in the grip of a political uprising, with the tiny island nation undergoing a massive campaign of civil disobedience against the ruling Khalifa family. Violence has escalated between protesters and security services, and frustration with the ineffectiveness of the peaceful protests has contributed to this.
One of the most prominent of the ongoing uprisings, and where the situation is worst, is Syria. The Syrian Army has besieged numerous cities to quell the rebellion against the government, which has ruled since 1963. It is estimated that 6,200 civilians have been killed, and politicians in Europe and the US are beginning to call for a Libyan-style intervention to prevent further civilian deaths in the country.
What is the international response to the situation in Syria?
Syria has presented a somewhat stickier situation than Libya - the violence enveloping the country has called for intervention, but unlike Libya, the international community's allegiances are not as clear cut.
World leader have overwhelmingly condemned the Assad regime for its violence, and major European leaders have called for the president to stand down.
However, other major world powers have been more ambiguous with their position towards the Syrian government.
China and Russia, who see the Assad regime as an important ally in the region, have vetoed security council resolutions calling for sanctions, as well as the Arab League's peace plan for the country.
Russia has also continued to provide the Syrian government with weapons. Russia has arms contracts estimated to be worth $1.5 billion with the Syrian government.
So what's next for the region? Will calls for freedom and democracy be as successful as they were in Egypt, Libya and Tunisia? Or will decreased media attention on countries where the struggle continues mean that the protests will be slowly muffled and repressed? 2012 will be the year we find out the real success of the Arab Spring.