the great wall of china - the timeless guardian of ancient china

morning reflection mountain evening landscape sunlight nature sunset dusk rock night dawn sunrise screenshot terrain sky cloud hill light great wall china timeless guardian ancient colossal structure stretching 000 miles one impressive well-known feats engineering human history originally constructed dynasties ming dynasty 1368–1644 served defense system invasions north mongols unesco world heritage site composed walls watchtowers fortresses natural barriers weaving rugged mountains deserts grasslands intricate design sheer scale