function show_region(region){
        var regions = new Array('europe','cis','asia','africa','australia','north-america','south-america');
        for (var i = 0; i < regions.length; i++){
            if (regions[i] != region){
                document.getElementById('mnu_' + regions[i]).style.display = "none";
                document.getElementById(regions[i] + '_image').style.display = "none";
            }
        }
        var mnu = document.getElementById('mnu_' + region);
        mnu.style.display = "block";
        document.getElementById(region + '_image').style.display = "block";
    }