could not get over the walls. take a look at that. that s the american flag at the u.s. embassy in cairo, but it s surrounded by those boulders, block after block after block. let s take a closer look at some of the potential u.s. targets. tom foreman is over at the magic wall. i think you have been hitting the fundamental point here. the old adage if you guard everything, you guard nothing, because there is a lot to guard out here. these are the main countries we re talking about out here. this is a tremendous amount of space and a tremendous number of potential targets. here is one we re talking about so much, yemen, which has been a problem for many years here. why would that be a potential place where you might have trouble? we have chatter suggesting a potential attack could come there according to security analysts. we ve had previous protests and attacks in that country many times, and there have been u.s. drone strikes there. so that s one reason that yemen might be a reasona