巍峨磅礴、气吞山河的万里长城,是中华民族的象征,也是世界上的伟大奇迹。从军事上说,它又是我国古代的一部宏伟的国防系统工程杰作。世人所熟知的是秦长城,而今人们所见到的或游览观光的则是明代修筑的长城。长城是由城演变来的。在原始社会,各氏族、部落为保卫自身的界域而筑墙,城即墙的发展。到了奴隶制时代,奴隶主为统治和保卫地方,就筑起城来。由城发展到长城,开始是由城堡或烽火台接连相望,以通警息;后来将城墙接连在一起,就是长城。筑长城最早的是齐 Towering majestic, breathtaking Great Wall, is a symbol of the Chinese nation, but also the great miracle in the world. From a military point of view, it is also a grand masterpiece of national defense system engineering in ancient China. The world is well known is the Great Wall of Qin, and now people see or sightseeing is the Great Wall built in the Ming Dynasty. The Great Wall is evolved from the city. In the primitive society, clans and tribes built walls to defend their own boundaries and the city was the development of the wall. By the time of slavery, the slave-owners built the city to rule and defend the place. From the development of the city to the Great Wall, starting from the castle or beacon one after another in order to catch the police; then the city wall together, that is, the Great Wall. Build the Great Wall is the first Qi