Great Wall of China winding through mountainous terrain under a clear blue sky

great wall of china winding aerial view mountains historic landmark china gubeikou heritage site unrestored architecture scenic panoramic travel tourism cultural heritage ancient structure clear sky landscape nature iconic sightseeing tourist attraction wilderness historical chinese culture fortification wall mountainous terrain outdoors hiking world heritage ancient defense structure beautiful scenery majestic exploration historic site history monumental travel destination famous landmark engineering marvel ancient architecture lush rugged terrain national pride historical monument long wall chinese history