The Chinese wall is made of dirt, mud, stone and brick. Lt is between 5 and 9 metres tall and up to 8 metres wide.A small road on the top of the wall. Towers every few hundred metres were built to store military supplies. They served as watch posts and were used to send information.guards fired cannonballs or used smoke signals to inform other towers of possible invaders.At times up to a million Chinese soldiers guarded the wall. Towards the end of the MiddleAges the great wall lost its military function