The Great Wall of China at Badaling

3. Restored section of the Great Wall

The Ming bricks were a marvel of engineering holding up to a pressure of over 1000 pounds per square inch. The mortar was of super strength. The mortar was stronger than the bricks themselves. The puzzle of this super strength has now been solved. The mystery ingredient was rice flour. With innovations like these, the Ming was able to build spectacular monuments. A feature of the wall was water drainage systems that channeled the water to the Chinese side and withheld the water to the enemy side and thus inhibiting plant growth and so deny cover to the attackers.