dr. samer attar: you work with the understanding that you gh crippled, or dismembered on the floor, next ying to save. >> pelley: dr. samer attar is a leading orthopedic surgeon from chicago, who volunteers in syria's makeshift hospitals. >> attar: the bombs would land so close, they'd knock you off your feet. and at times, they would directly hit the hospital. but all i did was look around and follow everyone else's lead, because they're like rocks. they don't lose their cool, they don't lose their composure. they just keep working. >> pelley: dr. attar enlisted in the syrian-american medical society, which began in the 1990s as a professional association. but, since the revolution, these american doctors have raised nearly $100 million in aid and sent more than 100 members into rebel-held syria, including aleppo, where dr. attar worked. >> attar: we'd find ourselves doing surgeries, sometimes without lying on gurneys in the hallway, because you're just so over- stretched. >> say hi, everybody. >> pelley: these are dr. attar's pictures of aleppo. >> attar: i remember another child that w