The first day of classes at School No. 66.<br /> <br />This is the industrial city of Mariupol in southeastern Ukraine.<br /> <br />All the trappings of back-to-school...<br /> <br />but bubbling just below the surface, tensions are high.<br /> <br />Last week, pro-Russian rebels fighting the government took a major town less than an hour's drive away.<br /> <br />They're threatening this strategic port city and residents are bracing for the rebel advance.<br /> <br />(SOUNDBITE) (Ukrainian) YEAR-11 STUDENT, MARIA MALYAR, SAYING:<br /> <br />"We don't even know what can happen tomorrow. So it is very difficult to plan anything for the future."<br /> <br />(SOUNDBITE) (English) YEAR-11 STUDENT, MYKHAILO SUKHAREV, SAYING:<br /> <br />"We want to say to all the other children of the world that we really want to have a peaceful life, like you have."<br /> <br />Ukraine's Education Ministry says all the schools where military action is underway are closed.<br /> <br />Less than half the schools in Donetsk and Luhansk, where rebels have their strongholds,
