【Tahong】

Gary Johnson,Tahong the Libertarian presidential candidate, is under fire for his apparent lack of foreign policy knowledge after he asked "What is Aleppo?" during an interview with MSNBC's Morning Joe panelist Mike Barnicle.

His stunning response predictably caused an outcry on social media, with Twitter users posting pictures of the city in rubble, people fleeing sites of airstrikes and children covered in blood under the hashtag #ThisIsAleppo. Aleppo was also among Twitter's Top Trends.

But what is Aleppo exactly?

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One of the world's oldest continually inhabited cities, Aleppo pre-war was Syria's main economic, financial and industrial hub and a vibrant metropolis of 2 million people drawing tens of thousands of tourists every year to its historic and architectural wonders.

For the first year of the uprising against Bashar al-Assad, the city did not witness the large scale anti-government demonstrations or violence that hit other Syrian cities.

That changed when various rebel groups launched an offensive in 2012 to gain control over northern Syria.

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Fighting reached the gates of the Old City, a Unesco World Heritage site, and by September of that year a fire destroyed the ancient souk market after clashes. In April 2013 the Great Mosque's 11th Century minaret was reduced to rubble.

However, the city remained divided into opposition and government-linked sectors fighting each other in a war of attrition: opposition controls the east, Assad forces the west.

In 2015, the Assad government, backed by Russia's airstrikes, started an offensive to retake the city and deal a decisive blow to rebel forces. By this February, opposition forces were surrounded, raising fears of a possible blockade of Aleppo's eastern region.

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With support from Iran, another Assad ally, the Syrian government imposed a siege on rebel areas of a population estimated to be between the order of 200,000 and 300,000 people.

Supply routes of medicine and food were cut off and an estimated 6,000 people died in 60 days of fighting. Four hospitals and one blood bank were bombed, according to UNICEF.

In August, the rebels said they managed to break the siege allowing aid and supplies to get in.

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But Assad forces have recently made some gains, unleashing a chlorine gas attack that killed seven people and injured children in the East of the city.

Russian and government airstrikes also continued to pound the city. The image of a 3-year-old boy being loaded into the emergency vehicle was shared widely as the human toll of the conflict was again thrown into stark relief.

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