Module6OldandNewTheGreatWallofChina,oneofthegreatestwondersoftheworld,wasenlistedintheWorldHeritagebytheUNESCOin1987
Justlikeagiganticdragon,theGreatWallwindsupanddownacrossdeserts,grasslandsandmountains,stretchingabout6,700kilometersfromeasttowestofChina
Withahistoryofmorethan2,000years,somepartsoftheGreatWallarenowinruinsorevenentirelydisappeared
However,itisstilloneofthemostappealingattractionsaroundtheworld
NoonecantellforsurewhenthebuildingoftheGreatWallwasstarted,butitispopularlybelievedthatitoriginatedasamilitaryfortificationagainstintrusionbytribesonthebordersduringtheearlierZhouDynasty
LateintheSpringandAutumnPeriod,somestatesextendedthedefenceworktopreventtheattacksfromotherstates
ItwasnotuntiltheQinDynastythattheseparatewallswereconnectedtoformadefensivesystembyEmperorQinShiHuan