NiagaraFallshasbecomeatiredoldtouristsight.Butifyoulookitoverinanairplane，itbecomessomethingcornpletelynew.Yourealizethatitisnottired；onlyourwayoflookingatitistired.MostvisitorsgoasclosetOthefallsaspossible，andwatchthewa—tersthunderingdown.Itisfascinating，inastupefyingway.Youstandthere，hyptonizedbythesheerforce，theuntiringactionthatgoesonandon.Butafterwardyouhaveafeeling一“Sowhat，really?ThewatercomestOthecliffand，naturally，itfallsdown.’’
Butataltitudeyouseeitallatonce.YouseeLakeOntarioononesideandLakeErieontheother，andlinkingthemthe34～mileNiagaraRiver.Then，comingdownlower，youseethefallsthemselves，alongafrontalmostamilewide，plungesovera182一footcliffandflowsoffthroughadeep，narrowgorge.Andrightaway，withaflashofunderstand—ing，youseethemainfactabouttheNiagaraFalls.Thefallsaremoving，theseven——mile——longgorgeismerelythetrackthefallshavemadeastheymovealong.Thisinstantlyreversesallyourideas.Onthegrounditseemedthatthewaterfellbecausetherewasthislowplaceforittofallintothegorge.Nowyouseeitistheotherwayround.Thefallsarethecause，andthegorgeistheresult.NiagaraGorgelookslikethetrackeatenintoanapplebyaworm.Niagaradiffersfromthewaterfallsyoufindinmountains，wherealackmassandcuttingpower.Niagarabelongstotheheavyweights—whereawholesolidriverplungesbodilyoveracliff.Therealsightfromaboveisthegiganticmovementofthefallsthemselves，diggingtheThefallsarestillmovingtoday.However，ourcenturyhastameditabit.A10tofwaterthatusedtoplungedownnowgoesthroughtheelectricpowerstations，bothAmericanandCanadian.Aboveintheair，youwillTheAmericanFallsgetonlyabout10％ofthewater.whiletheCa—nadianFallsget90％。Becausethevolumeofwaterisgreater.theCanadi—anFallsareerodingfarmorerapidly.UnlikethemountainsandcanyonsOfmeWest.Niagaraisashort—timeglorythatwashereyesterdayand
fascinatinga.迷人的，有極大吸引力的altituden.高度，海拔；[p1.]高處，高地instantlyad.立即，立刻wormn.蟲，蠕蟲rapidlyad.迅速地；險峻地understandingn.協議；理解（力）；相互理解