the great wall of china

abandoned ancient arch architecture asia asian attraction autumn backpacking badaling barrier beijing border brick building built castellated china chinese crenulated culture day defence door dynasty east eastern fall famous great heritage hike hill historic history jinshanling landmark long mandarin mountain mountains neglected old orient oriental path peking protection roof ruins section security serpentine simatai sites sky stair staircase stairs steps stone structure sun tourism tourist tower travel traveler traveller tree trek vacation view walk walking wall watch watchtower wonder world