the soldiers showed us a tunnel and bunker complex they just discovered. >> be careful where you step. there is a concern these could be booby trapped. the far end, came to an isis headquarters. food still in the kitchen area. half made bombs. chemicals for more. and on the wall, what has become one of the most infamous symbols anywhere. the isis logo. more often than not, when americans were standing in front of this, they were about to be beheaded. isis brutally killed many more iraqis. today, it was their turn to have isis on the run. but reaching mosul, the isis stronghold, may just be the easy part. >> richard engel there for us in iraq. hillary clinton gaining ground in a critical battleground state. mark murray at the map with our poll of the day. we also have a new poll since