gainingheight,whentheplanesuddenlyturnedroundandflewbacktotheairport.Whilewewerewaitingtoland,anair-hostesstoldustokeepcalmandtogetofftheplanequietlyassoonasithadtoucheddown.Everybodyonboardwasworriedandwewerecurioustofindoutwhathadhappened.Laterwelearntthattherewasaveryimportantpersononboard.Thepolicehadbeentoldthatabombhadbeenplantedontheplane.Afterwehadlanded,theplanewassearchedthoroughly.Fortunately,nothingwasfoundandfivehourslaterwewereabletotakeoffagain.Lesson80TheCrystalPalace水晶宫PerhapsthemostextraordinarybuildingofthenineteenthcenturywastheCrystalPalace,whichwasbuiltinHydeParkfortheGreatExhibitionof1851.TheCrystalPalacewasdifferentfromallotherbuildingsintheworld,foritwasmadeofironandglass.Itwasoneofthebiggestbuildingsofalltimeandalotofpeoplefrommanycountriescametoseeit.Agreatmanygoodsweresenttotheexhibitionfromvariouspartsoftheworld.Therewasalsoagreatdealofmachineryondisplay.ThemostwonderfulpieceofmachineryonshowwasNasmyth'ssteamhammer.Thoughinthosedays,travellingwasnotaseasyasitistoday,steamboatscarriedthousandsofvisitorsacrosstheChannelfromEurope.OnarrivinginEngland,theyweretakentotheCrystalPalacebytrain.Thereweresixmillionvisitorsinall,andtheprofitsfromtheexhibitionwereusedtobuildmuseumsandcolleges.Later,theCrystalPalacewasmovedtoSouthLondon.Itremainedoneofthemostfamousbuildingsintheworlduntilitwasburntdownin1936.Lesson81Escape脱逃Whenhehadkilledtheguard,theprisonerofwarquicklydraggedhimintothebushes.Workingrapidlyinthedarkness,hesoonchangedintothedeadman'sclothes.Now,dressedinablueuniformandwitharifleoverhisshoulder,theprisonermarchedboldlyupanddowninfrontofthecamp.Hecouldhearshoutinginthecampitself.Lightswereblazingandmenwererunninghereandthere:theyhadjustdiscoveredthataprisonerhadescaped.Atthatmoment,alargeblackcarwithfourofficersinsideit,stoppedatthecampgates.Theofficersgotoutandtheprisonerstoodtoattentionandsalutedastheypassed.Whentheyhadgone,thedriverofthecarcametowardshim.Themanobviouslywantedtotalk.Hewasratherelderlywithgreyhairandclearblueeyes.The