The Great Wall is a series of stone and earthen fortifications in China, built, rebuilt, and maintained between the 5th century BC and the 16th century to protect the northern borders of the Chinese Empire during the rule of successive dynasties.alls were being built in order to protect the Chinese empire as early as the 7th century BC. However, the collection of walls which have become known as The Great Wall of China were mainly built from 220 to 206 BC.