The Great Wall of China is the largest construction on earth, and the subject of the most mythology. These walls stretch over many thousands of miles in total, and stand in various stages of disrepair or restoration. Later dynasties sometimes restored and rebuilt along a line established by their predecessors. Long sections are fragmentary, decayed by the passage of time, the growth of vegetation and the removal by local people of large amounts of core material for buildings. The height, width and construction all vary widely. The natural tendency was to use material available locally, so its composition mutates with the scenery, from a rude line of mud and wattles to the elaborate stonework of the Ming Daynasty Wall.