>> reporter: i don't know exactlt. what it certainly is going to mean is more police, more military out inhe streets, a lot more people being deployed, more checkpoints, people being -- people being search add cross the city. i mean this is -- when a city like this goes into its highest alert level, you now will visibly see what might have been security forces who were in thehe shadows who were being very subtbt suddenly coming out in a show of force. they were be extremely visible, for example, in brussels, the main tourist attractiom is the center square. like times square so i imagine what's happening right now they're setting up a perimeter around that. looking at the people who are going in, looking at their i.d.s and purses and bags and that sort of thing so what might have been a more laid back but heightened sense of securitys now going to be a lot more proactive and visible. >> one of the troubling things about these, while you did have dual explosions here oftentimes as you know you covered the attacks in par