Along the northern border of Italy --- seen the Alps,mightly

这是个倒装句。一般语序是The Alps,mightly in their splendor,are seen along the 。。。但若这样说的话,会把主语和谓语分开,不合习惯,故倒装。群岛、山脉、海峡、瀑布等地理名称,通常作复数用。后面mightily in their splendor修饰the Alps,故人称代词也用复数。句子的意思是：沿着意大利的北部边境可以看到阿尔卑斯山,十分雄伟壮丽。