Tunneling is a classic tactic used for guerrilla warfare, one that Syrian rebel forces have in Syria to . Yet the size of this underground detonation is unprecedented, even for this bloody conflict. The building is there and then, moments later, it's gone.

(The explosion comes at about 0:48 into the video, but does show a building blowing up that reportedly had people inside)

The northern Syrian city of Aleppo continues to smolder after years of fighting as Rebel forces go on an offensive to push back Assad's forces' recent gains. Apparently, a group of rebel fighters tunneled under what was once the Chamber Of Industry, being used as a command and control facility for Assad's forces at the time of the blast, and planted a massive bomb. As the video shows, the explosion literally vaporized the structure above it and send debris flying high into the air.

The , but numerous people are assumed to have been killed in the attack.

Sunday's attack came after "Islamist rebel bridges blew up a building housing the Chamber of Industry in the Old City, which was being used as a headquarters by government forces," the Observatory said.

The group reported dead and wounded among soldiers in the building, and said there was fighting ongoing in the area.

State television meanwhile said that "terrorist groups have blown up several building... including the Chamber of Industry."

Airstrikes against Syrian rebels are said to have intensified, the main weapon of choice being the gruesome "barrel bomb." These improvised devices, usually dropped out of helicopters, are barrels packed with explosives and nails, creating a massive blast and throwing shrapnel over a wide radius. Meanwhile, rebels have attacked a power station that intermittently fed Aleppo and have blocked roads that bring Assad's forces supplies into the city. Thus the city has plunged into darkness for the foreseeable future. Basically Aleppo is in a state of total warfare, where any and every tactic is being used by both sides to kill, maim and demoralize the enemy.

Meanwhile, for the first time ever, Iraq has sent attack helicopters into Syria to take out a convoy of fundamentalist fighters and supplies that were attempting to enter Iraq's troubled western Anbar Province. Apparently the convoy was attempting to make its way to Fallujah, the never ending war zone of a city where Iraqi security forces are fighting Islamic Fundamentalists for control.

Although it has been known that some Islamic extremist rebel forces in Syria are sharing fighters and material with those in Iraq, there has never been any actions taken by Iraq outside of its own borders regarding the issue. This new precedent may be a sign of things to come as both countries continue to sink deeper into unrest.