万里长城在我国北方辽阔的土地上,东西横亘着一道绵延起伏、气势雄伟、长达一万多里的长墙.这就是被视为世界建筑史上一大奇迹的万里长城.万里长城是我国古代一项伟大的防御工程它凝聚着我国古代人民的坚强毅力和高度智慧,体现了我国古代工程技术的非凡成就,也显示了中华民族的悠久历史. 　　长城是中国也是世界上修建时间最长、工程量最大的一项古代防御工程.自公元前七八世纪开始,延续不断修筑了2000多年,分布于中国北部和中部的广大土地上,总计长度达50000多千米,被称之为“上下两千多年,纵横十万余里”.如此浩大的工程不仅在中国就是在世界上,也是绝无仅有的,因而在几百年前就与罗马斗兽场、比萨斜塔等列为中古世界七大奇迹之一. 　　准确地说,长城不只有一座.在两千多年间,各代王朝在中国的北方修建了许多座长城.其中,最"新"的而且也是目前保存最完整的一座建于中国明代（1368－1644）. 　　明长城是一座结构庞大复杂的边防堡垒,绵延6700公里.它是世界最伟大的人工奇迹. 　　明长城翻山越岭,蜿蜒迂回于崇山之间.看见它人们不由肃然起敬,感叹在如此险峻的地方使用数量如此众多而且巨大的建筑材料.长城见证了古代中原农业文明和北方游牧民族间剑拔弩张的激烈对抗. 　　明代长城是人类历史上耗费人力最巨,时间最久,物资最多的建筑.这使它成为一件最大的历史文物.在今天这个瞬息万变的世界,保护长城是文化遗产保护领域最具挑战性的任务. 　　GreatWallisinthenorthernpartofourcountryonvastland,thethingspansisbeingcontinuousthefluctuationtogether,imposing,longreachesmorethan10,000mileslongwalls.ThisisregardedasintheworldhistoryofarchitectureabigmiracleGreatWall.TheGreatWallwasourcountryancienttimesagreatdefenseprojectitiscondensingourcountryancienttimespeople'sstrongwillandhighlythewisdom,hasmanifestedourcountryancienttimestheprojecttechnologyextraordinaryachievement,alsohasdemonstratedChinesenation'sglorioushistory. 　　TheGreatWallwasChinaalsoisintheworldtheconstructiontimeislongest,aresiliencebiggestitemofancienttimesdefendstheproject.StartsfromtheB.C.E.78centuries,theextensionhasconstructedunceasinglyformorethan2000years,distributesinthenorthernChinaandonthemiddlegenerallands,amountstothelengthtoamounttomorethan50000kilometers,iscalledit“aboutmorethan2000years,verticallyandhorizontally100,000miles”.NotonlythesovastprojectinChinaisintheworld,alsoisunique,thusinseveralhundredyearsagoonwiththeRomanarena,theLeaningTowerofPisaandsoonlistsasoneofMiddleAgesworldsevenwondersoftheworld. 　　Accuratelyspeaking,GreatWallnotonlythen.Induringmorethan2000years,eachgenerationofdynastyhasconstructedmanyGreatWallinChina'snorth.Amongthem,most"new"moreoveralsoisatpresentpreservesmostcompleteonetoconstructattheChineseMingDynasty(1368-1644). 　　ThebrightGreatWallisastructurehugecomplexborderdefensefortress,iscontinuous6700kilometers.Itistheworldgreatestartificialmiracle. 　　ThebrightGreatWallgoesoverhillanddale,windsbetweencircuitousYuChongshan.Seesitspeoplebynottohaveprofoundrespectfor,sighedissomultitudinousinthesoprecipitousplaceusequantitymoreoverthehugebuildingmaterial.GreatWalltestimonyancienttimesareasouthofYellowRiveragriculturecivilizationandnorthbetweennomadsatdaggersdrawnintenseresistance. 　　TheMingDynastyGreatWallisinthehumanhistoryconsumesthemanpowertobegreatest,thetimeismostlong,commoditymostconstructions.Thiscausesittobecomebiggesthistoricalrelics.Intodaythisfastchangingworld,protectstheGreatWallistheculturalheritageprotectiondomainmostchallengingduty.