special town hall event on gun violence. you'll see it live only here on cnn. i'm wolf blitzer, you're in "the situation room." paris gets a new terror scare a year to the day after a bloody attack on the "charlie hebdo" magazine. french officials say a knife wielding man is shot dead as he tried to enter a police station. they say the assailant had a fake explosive device and carried an isis symbol. it's the latest in a wave of terror including the november 13th slaughter over 130 people and attacks claimed by isis. and we have new satellite images showing activity at the suspected test site where north korea set off some sort of nuclear blast. north is celebrating what it calls a hydrogen bomb test. the u.s. and its allies are skeptical, but are scrambling to try to learn exactly what kim jong-un's regime exploded. south korea plans to celebrate the north korean leader's birthday in the coming hours