in less than 24 hours. those incidents raising questions about whether europe s terror threat is increasing. a new report saying up to 3,000 fighters could soon return to europe from the middle east. in france alone 269 people have already returned. let s bring in the director of push in united for israel s watchman project. he s the host of the watchman show and a terrorism analyst. thanks for being here. sandra, good to be with you. sandra: so, we re left with this question. how do we prevent attacks like this from happening in the future? very difficult, sandra. i was in london last month on westminster bridge. they put guardrail ors bare kwrers there on that bridge. i think in one sense you re going to see a physical reaction to it. probably more barriers on crowded tourist spots, on bridges, in western capitals. i think more importantly, we need to be able to identify