The Syrian government has been using barrel bombs, bombs that are made up of various explosives, nails, metal fragments, and sometimes even chemicals, since early on in the country's civil war. They're the type of bombs used by the US in the Vietnam War.
Syrian President Bashar al-Assad has denied using these easy-to-make bombs, but neither rebel groups nor the Islamic State have helicopters from which to drop them.
The Syrian government started using these barrel bombs after running out of more sophisticated air-to-ground ones. In Aleppo alone, they've killed 3,000 civilians between January 2013 and March 2014. Now, the Islamic State is using the civilian deaths caused by these bombs as a powerful recruiting tool.
Story by Allan Smith and editing by Carl Mueller
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