ALEPPO, Syria — Abu Ahmad, who lives in Aleppo's rebel-controlled east, had grown accustomed to sending money at the end of every month to his business partner living in the regime-controlled western part of the city. Abu Ahmad, in his 40s, did not know that the war would one day lead him to open a money transfer office to coordinate cash flow between the two parts of the city.

The border between east and west extends for more than 11 kilometers (6.8 miles). Along it, one sees sandbags, large piles of debris, burnt buses parked on top of each other and hundreds of snipers. It is impossible for anyone to cross the border, lest they be shot dead by snipers.

Ironically, the only crossing, known as "Garage al-Hajz," which was the only corridor for civilians to move between the two parts of the city before the regime shut it down in February, is called the crossing of death, as more than 216 people have been killed by snipers while crossing.

Dozens of sniping operations were regularly witnessed at Garage al-Hajz. Regime snipers are deployed on the rooftop of the municipality building, which is the highest building in Aleppo and directly overlooks the crossing.