nearly five years of civil war has made syria one of the most dangerous places to live. amid the tragedy, there is heroism. the white helmets who serve as first responders. cnn's dr. sanjay gupta has this exclusive. >> you're watching an extraordinary rescue in aleppo syria. for 12 hours these men have been digging and drilling. and they're about to save the life of a 2 week old baby. the baby saviors only known by what they wear. they are the cavalry. the white helmets.