Syria's rebels surprise the regime in Aleppo
The blackened carcasses of tanks and military supply vehicles on the streets of Aleppo's vast Sunni suburb are a testament to the battles already fought here.
A group of rebel fighters climbed aboard one of the tanks, waved their Kalashnikov rifles in the air, singing and chanting for the downfall of the family and party that has ruled them for more than four decades.
Abu Mohammed explained how they had prevailed: "We went through the back streets and attacked the convoy from the side with rocket-propelled grenades."
Some of the houses nearby had large, irregular-shaped holes punched into them by tank fire. Another had collapsed in on itself.
An old man with a worn face called Abdulrahman introduced himself as the owner of the house.
He said, "Before when we tried to demonstrate, bullets came from everywhere, but now we feel safe because the Free Syrian Army controls this area, they protect us."
The debris of rubble and twisted metal parts on the road marks a small defeat for the army and a gross miscalculation by local military commanders as to the strength of the rebellion they face in the city.
Perhaps with good cause. With the exception of peaceful protests by students at the university and others in some outlying districts, Aleppo has seen hardly any of the fighting and deaths that have occurred across Syria.
That all changed in the last six days as clashes erupted in a handful of districts, quickly spreading to others. The Free Syrian Army claims to control 70% of neighbourhoods in Aleppo.
That is impossible to independently verify - and what will determine the outcome is not their level of "control" but their capacity to resist.
What changed here is that large numbers of fighters and quantities of weapons and ammunition were smuggled in from across this large northern province. The rebels have been involved in months of fierce fighting and are battle-hardened and experienced.
They now appear to be receiving a steady flow of ammunition and some weapons, albeit small arms and rocket-propelled grenades. Much of it seems to be coming across the increasingly porous border from Turkey.
So when government troops tried to wrest back control of the rebellious districts they were simply unprepared for the strength of the resistance.
Not any more - restive neighbourhoods are now being pounded by artillery, mortars and helicopter gunfire with unverified reports of large-scale reinforcements heading to the city.
Tuesday marked a significant escalation by the military when air-force jets took to the skies, strafing rebel positions. We watched as the planes swooped low, banking and firing to the ground. It is a mark of how serious the fight here is and the government's desperation to hold onto the city.
We heard the crash and thump of artillery and mortar shells landing and exploding nearby and the near constant sound of gunfire. Snipers from both sides exchanged high-calibre shots as the volleys from street battles grew through the day.
Helicopters controlling the skies poured machine-gun fire to the ground as the rebels tried in vain to bring them down.
So the battle for Aleppo is now raging and it is one neither side can afford to lose.
The historic city is not only the largest in the country but its economic heart. The government derives material support from its merchant class and vital industries that supply the rest of the country.
The stakes could not be higher. For the armed opposition losing would be a disastrous setback that, at the very least, could neuter their revolution for months. For President Bashar al-Assad, losing Aleppo could be the tipping point that presages the downfall of his government.
Despite their confidence and commitment, the rebels remain vastly outgunned and, with reinforcements from the army, outmanned, and it is hard to see how they can prevail.
But many people here are desperate for the rebels to succeed, clamouring for the freedoms denied to them by their president and the ruling Ba'ath Party. They certainly enjoy widespread support in these vast poor suburbs from their fellow Sunni Muslims.
The opposition says it fights in the name of freedom and democracy. The government says its men are simply terrorists.
Many of the wealthier Sunni middle classes here share that view and, fearing economic ruin, they have sided with the government.
Aleppo is also home to a significant minority of Christians who have been reluctant to side with the opposition.
And as the rebels take over districts in the city many fear that what is really happening is an Islamic takeover that will unleash a whirlwind of sectarian division and bloodshed across this region.
Pools of blood
Inevitably the flow of casualties has increased as the fighting intensifies.
Wounded fighters and screaming civilians were brought to a secret makeshift hospital for emergency treatment before being whisked away.
The floor is filthy with grime and pools of blood. With only paltry supplies the volunteer doctors struggle to help.
The UN estimates more than 10,000 people have died in a conflict that only continues to escalate.
The response from the international community has simply had no impact on the ground. However the battle for Aleppo ends, many more innocent people are likely to be killed, as both sides appear ready to fight to the bitter end.