-- construction continued --

Secrets of the Construction of the Ming Wall

The Ming period pushed wall-building technologies to the limit. The Ming wall snakes acrobatically across some of China's most forbidding terrain, rising in places at an angle of 70 degrees.

The Ming Wall was built mainly of brick, stone or the two materials in mixture. The wall body was surfaced with bricks or long narrow stones; the chinks were filled with lime mortar so even and tight that grass and shrubs were difficult to root in them; along the top, a channel was opened to drain rain water and protect the wall.

While in the Loess Plateau region of northwestern China, the Ming Wall was largely built of rammed earth or adobe, comparable to brick and stone in solid durability. For example, the Jiayuguan section in Gansu was made of loess specially carried from Heishan Hill some dozen km west of the Pass; the earth was tamped compact with ram impressions tightly connected with each other so as to prevent the wall body from deformation and break.

Such dramatic engineering wouldn't have been possible without the Ming's advanced brick-making technology. At a time when European builders were still relying upon cumbersome cut stone, the Ming were using state-of-the-art kilns to mass produce bricks, which were as strong as modern-day masonry blocks.

Along the Great Wall, castles were built at road intersections of strategic significance, dangerous defiles and junctions between the mountain and the seaboard for transportation and defense purpose. When the wall crossed over a river, a water gate would be constructed beneath the wall body to let the stream flow on.