TianmenMountainwascalledYunmengMountaininancienttimes,alsoknownasYupingmountain.Itislocated10kilometerssouthofZhangjiajieCity.In263ad,becauseofthecollapseofthemountainwall,adoorwasopenedintheupperpartofthemountain,connectingthenorthandthesouth.DuringtheThreeKingdomsperiod,sunXiu,kingofWu,thoughtitwasauspiciousandnamedit"TianmenMountain".Tianmencaveislocatedonthecliffatanaltitudeofmorethan1260meters.Itis131.5metershigh,57meterswideandmorethan60metersdeep.Accordingtotheresearchofgeologicalexperts,thecentralpartoftheentranceistheintersectionofthesynclineoftheEastandWestrocklayers.Duetothecompression,therockwasbrokenandcollapsed,andtheentrancewasfinallyformedin263.TianmenMountainis1517.9metersabovesealevel.BecausetherelativeheightdifferencebetweenTianmenMountainanddowntownareaismorethan1300meters,TianmenMountainisespeciallytallandstraight.ItsbeautifulskylineisatypicalexampleofTianmenMountain.
TianmenMountainisanational5Atouristarea.Itisalsoknownas"China's50mostworthyplacesforforeignerstovisit,China'smostdesirableplaces,Hunan'snewXiaoxiangeightscenicspots,China'stop100selfdrivingscenicspots,andChina'stop10scenicspotsmostconcernedbyInternetusers".
TheuniquekarstplatformlandformofTianmenMountainisrareallovertheworld.Itisaisolatedmountainwithprecipicesaroundit.Theheightdifferencewithinafewkilometersreachesmorethan1300meters,whichcreatesthemagnificentmomentumofthetoweringisolatedpeak.Thetoppartofthemountainisrelativelyflat,coveringanareaof2squarekilometers,withaforestcoveragerateof90%.Therearemanystrangerocksandtrees.IthasarareDavidiainvolucratacommunityintheworld.Itiswildallyearround,justlikeabeautifulskygarden.InJuly1992,TianmenMountainwasapprovedbytheMinistryofforestryasthesecondNationalForestParkinZhangjiajie.ThepoetWangXinjian'spoem"walkingonTianmenMountain"says:"Iwanderedforalongtimeinmydreamsseveraltimes,andthebreezecametenlitostepontheflowers.Stepbystep,theskystepsleadtothesilverHan,andthevastcloudpathencirclesthegreencliff.Theancienttemplesarehiddeninthesecludedvalley,andthescreenisruggedandmovingtoPenglai.Andbathethehazeintothewonderland,alreadyChengxinnearYaotai."