（美墨边境墙，阻隔的只是骨肉亲情）BOUNCINGALONGAdustyBavarianloggingroad,archaeologistClaus-MichaelHüssenkeepshiseyesonthetreelinetotheleft,searchingforsomefamiliarlandmarkinthethickforest.Suddenlyhepullsthevanoverandgetsout,pausingtopacktobaccointohispipeandconsulta1:50,-scalesurveymap.考古学家克劳斯·迈克尔·胡森沿着尘土飞扬的巴伐利亚伐木小路颠簸行进，同时注视着左手边的树林，在茂密的森林中搜寻某种熟悉的地标。突然，他停车走下来，将烟叶裹好，塞进烟斗，然后仔细查看1:50的勘察图。Headdown,pipeinhand,Hüssen—aresearcherwiththeGermanArchaeologicalInstitute—crossestheroadandwadesthroughthethickunderbrush.Fiftyyardsfromtheroad,henearlymissesalowdirtmoundaboutthreefeethighandsixfeetacross.Litteredwithflatwhitestones,itrunsinanunnaturallystraightlinealongtheforestfloor.胡森是德国考古研究所的研究员。他手拿烟斗向下走，穿过草丛间的小路、溪流。在离小路50码的地方，他差点忽略了一条3英尺高、6英尺宽的土堆。土堆在林地间向前延伸，形成笔直的线条，周围散布着平滑的白色石头。Nearly2,yearsagothiswasthelinethatdividedtheRomanEmpirefromtherestoftheworld.HereinGermanythelowmoundisallthat’sleftofawallthatoncestoodsometenfeettall,runninghundredsofmilesunderthewaryeyesofRomansoldiersinwatchtowers.大约2年前，这是罗马帝国与外部世界的分野。眼前这矮小的土堆，曾经是高达10英尺、绵延数百英里的城墙，被瞭望塔上的罗马士兵密切监视着。Itwouldhavebeenashockingsightinthedesolatewilderness,milesnorthofRomeitself.“Thewallherewasplasteredandpainted,”Hüssensays.“Everythingwassquareandprecise.TheRomanshadadefiniteideaofhowthingsshouldbe.”Engineeringstudentsmeasuringanotherstretchofwallfoundone31-milesectionthatcurvedjust36inches.在这一片荒凉萧瑟之地，离罗马英里的城墙曾经是一道震撼人心的风景。胡森介绍道：“城墙被精心粉刷、装饰，一切都显得严整、精密。罗马人执着于事物的完美状态。”测量另一段城墙的工程专业学生发现：长达31英里的城墙只有36英寸的偏离。Hüssenfacesnorth,theRomanEmpireathisback.Twohundredyardsaway,justpastanarrowmeadowtornupbywildboarsandarushingstream,thenexthillriseslikeagreenwall.“Here’stheborder,”hesays,“andontheothersideisawonderfulviewofnothing.”胡森面对着北方，后面就是罗马帝国。码以外，越过一片被野猪踩乱的狭窄的草地和奔流的小溪，临近的山丘有如绿色的城墙。胡森说：“那就是边境，而山丘的另一边则是满目苍凉。”Astunningnetworkofwalls,rivers,desertforts,andmountainwatchtowersmarksRome’slimits.AtitspeakinthesecondcenturyA.D.,theempiresentsoldierstopatrolafrontthatstretchedfromtheIrishSeatotheBlackSeaaswellasacrossNorthAfrica.城墙、河流、城堡、瞭望塔组成的复杂网络宣示着罗马的国界。在公元2世纪罗马的巅峰时期，帝国派遣兵士驻守各处要塞，遍及爱尔兰海到黑海以及北非的辽阔疆域。Hadrian’sWall,inEngland,probablythebestknownsegment,wasnamedaUNESCOWorldHeritagesitein.In5UNESCOestablisheda