The biggest wall of the world is the Great Wall of China. The Chinese name of the Great Wall of China is ‘Changcheng’. It is the longest structure ever built by humans. It stretches around 6,300 kilometres (3915 miles) in length. The widest section of the wall is around 9 metres (30 feet). The highest point of the wall is around 8 metres (26 feet). It is made up of a number of sections built by various dynasties over a long period of time. Its main purpose was protection against attacks from the north.