TheGreatWall，likethePyramidsofEgypt，theTajMahalinIndiaandtheHangingGardenofBabylon，isoneofthegreatwondersoftheworld.StartingoutintheeastonthebanksoftheYaluRiverinLiaoningProvince，theWallstretcheswestwardsfor12，700kilometerstoJiayuguanintheGobidesert，thusknownastheTenThousandLiWallinChina.TheWallclimbsupanddown，twistsandturnsalongtheridgesoftheYanshanandYinshanMountainChainsthroughfiveprovinces-Liaoning，Hebei，Shanxi，Shaanxi，andGansu--andtwoautonomousregions--NingxiaandInnerMongolia，bindingthenorthernChinatogether.HistoricalrecordstracetheconstructionoftheoriginoftheWalltodefensivefortificationbacktotheyear656B.C.duringthereignofKingChengoftheStatesofChu.ItsconstructioncontinuedthroughouttheWarringStatesperiodinthefifthCenturyB.C.whenducalstatesYan，Zhao，Wei，andQinwerefrequentlyplunderedbythenomadicpeopleslivingnorthoftheYinshanandYanshanmountainranges.Walls，then，werebuiltseparatelybytheseducalstatestowardoffsuchharassments.Laterin221B.C.，whenQinconqueredtheotherstatesandunifiedChina，EmperorQinshihuangorderedtheconnectionoftheseindividualwallsandfurtherextensionstoformthebasisofthepresentgreatwall.Asamatteroffact，aseparateouterwallwasconstructednorthoftheYinshanrangeintheHanDynasty，whichwenttoruinthroughyearsofneglect.Inthemanyinterveningcenturies，succeedingdynastiesrebuiltpartsoftheWall.ThemostextensivereinforcementsandrenovationswerecarriedoutintheMingDynastywhenaltogether18lengthystretcheswerereinforcedwithbricksandrocks.itismostlytheMingDynastyWallthatvisitorsseetoday.TheGreatWallisdividedintotwosections，theeastandwest，withShanxiProvinceasthedividingline.Thewestpartisarammedearthconstruction，about5.3metershighonaverage.Intheeasternpart，thecoreoftheWallisrammedearthaswell，buttheoutershellisreinforcedwithbricksandrocks.ThemostimposingandbestpreservedsectionsoftheGreatWallareatBadalingandMutianyu，notfarfromBeijingandbothareopentovisitors.TheWallofthosesectionsis7.8metershighand6.5meterswideatitsbase，narrowingto5.8metersontheramparts，wideenoughforfivehorsestogallopabreast.Thereareramparts，embrasures，peep-holesandaperturesforarchersonthetop，besidesgutterswithgargoylestodrainrain-waterofftheparapetwalk.Two-storiedwatch-towersarebuiltatapproximately400-metersinternals.Thetopstoriesofthewatch-towerweredesignedforobservingenemymovements，whilethefirstwasusedforstoringgrain，fodder，militaryequipmentandgunpowderaswellasforquarteringgarrisonsoldiers.Thehighestwatch-toweratBadalingstandingonahill-top，isreachedonlyafterasteepclimb，like"climbingaladdertoheaven".Theviewfromthetopisrewarding，hoverer.TheWallfollowsthecontourofmountainsthatriseonebehindtheotheruntiltheyfinallyfadeandmergewithdistanthaze.Asignalsystemformerlyexistedthatservedtocommunicatemilitaryinformationtothedynasticcapital.ThisconsistedofbeacontowersontheWallitselfandonmountaintopswithinsightoftheWall.Attheapproachofenemytroops，smokesignalsgavethealarmfromthebeacontowersinthedaytimeandbonfiredidthisatnight.
    Emergencysignalscouldberelayedtothecapitalfromdistantplaceswithinafewhourlongbeforetheinventionofanythinglikemoderncommunications.Therestand14majorpassesatplacesofstrategicimportancealongtheGreatWall，themostimportantbeingShanghaiguanandJiayuguan.YetthemostimpressiveoneisJuyongguan，about50kilometersnorthwestofBeijing.Knownas"TianXiaDiYIGuan"，ShanghaiguanPassissituatedbetweentwosheercliffsforminganeckconnectingnorthChinawiththenortheast.Ithadbeen，therefore，akeyjunctioncontestedbyallstrategistsandmanyfamousbattleswerefoughthere.ItwasthegateofShanghaiguanthattheMinggeneralWuSanguiopenedtotheManchuarmytosuppressthepeasantrebellionledbyLiZichengandsosurrenderedthewholeMingempiretotheManchus，leadingtothefoundationoftheQingDynasty.JiayuguanPasswasnotsomuchasthe"StrategicpassUndertheHeaven"asanimportantcommunicationcenterinChinesehistory.Cleftbetweenthesnow-cappedQilianMountainsandtherollingMazongMountains，itwasontheancientSilkRoad.ZhangQian，thefirstenvoyofEmperorWuDioftheWesternHandynasty，crosseditonhisjourneytothewesternregions.Later，silkflowedtothewestthroughthispasstoo.Thegate-towerofJiayuguanisanattractivebuildingofexcellentworkmanship.Ithasaninnercityandanoutercity，theformersquareinshapeandsurroundedbyawall11.7metershighand730metersincircumference.Ithastwogates，aneasternoneandawesternone.Oneachgatesitsatowerfacingeachother.thefourcornersofthewallareoccupiedbyfourwatchtowers，oneforeach.Juyongguan，agatewaytoancientBeijingfromInnerMongolia，wasbuiltina15-kilometerlongravineflankedbymountains.ThecavalrymenofGenghisKhansweptthroughitinthe13thcentury.AtthecenterofthepassisawhitemarbleplatformnamedtheCloudterrace，whichwascalledtheCrossing-StreetDagoba，sinceitsnarrowarchspannedthemainstreetofthepassandonthetopoftheterracethereusedtobethreestonedagobas，builtintheYuanDaynasty.Atthebottomoftheterraceisahalf-octagonalarchgateway，interestingforitswealthofdetail:itisdecoratedwithsplendidimagesofBuddhaandfourcelestialguardianscarvedonthewalls.Thevividnessoftheirexpressionsismatchedbytheexquisiteworkmanship.suchgrandioserelicsworks，withseveralstonespiecedtogether，arerarelyseeninancientChinesecarving.Thegatejambsbearamulti-lingualBuddhistsutra，carvedsome600yearsagoinSanskrit，Tibetan，Mongolian，Uigur，HanChineseandthelanguageofWesternXia.Undoubtedly，theyarevaluabletothestudyofBuddhismandancientlanguages.Asaculturalheritage，theWallbelongsnotonlytoChinabuttotheworld.TheVenicechartersays:"Historicalandculturalarchitecturenotonlyincludestheindividualarchitecturalworks，butalsotheurbanorruralenvironmentthatwitnessedcertaincivilizations，significantsocialdevelopmentsorhistoricalevents."TheGreatWallisthelargestofsuchhistoricalandculturalarchitecture，andthatiswhyitcontinuestobesoattractivetopeopleallovertheworld.In1987，theWallwaslistedbyUNESCOasaworldculturalheritagesite.Notes:1.theTajMahalinIndia印度的泰姬陵2.theHangingGardenofBabylon巴比伦的空中花园3.Sanskrit梵语4.Uigur维吾尔语
    Therestand14majorpassesatplacesofstrategicimportancealongtheGreatWall，themostimportantbeingShanghaiguanandJiayuguan.YetthemostimpressiveoneisJuyongguan，about50kilometersnorthwestofBeijing.
    Knownas"TianXiaDiYIGuan"，ShanghaiguanPassissituatedbetweentwosheercliffsforminganeckconnectingnorthChinawiththenortheast.Ithadbeen，therefore，akeyjunctioncontestedbyallstrategistsandmanyfamousbattleswerefoughthere.ItwasthegateofShanghaiguanthattheMinggeneralWuSanguiopenedtotheManchuarmytosuppressthepeasantrebellionledbyLiZichengandsosurrenderedthewholeMingempiretotheManchus，leadingtothefoundationoftheQingDynasty.