The Great Wall of China is an historic border fortification. It was intended to protect the Chinese Empire from the nomadic tribes of horseman in the north. The Great Wall of China is the largest edifice in the world. It has a total length of 8,851.8 km, with the main wall stretching for 2,400 km. The individual sections of the wall are made up of different systems. They vary in age and method of construction – and, in parts, are not even connected to each other. The name Wànlǐ Chángchéng (“10,000 Li long wall”) refers to the length specification of 10,000 Li. This number also represents infinity in the Chinese language. Therefore the phrase means something like “unimaginably long wall”. The wall undergoes constant restoration, with the most well-known restored section being 70 km northwest of Beijing.