The Great Wall of China is the only man-made structure that is visible from the distance of about 300,000 Km from earth i.e. from the moon. Truly speaking, Great Wall of China is one of the wonders that man ever have created. The Great Wall extends from the Jiayu Pass in Western Gansu Province to the Eastern mount of the Yalu River in Liaoning Province. The Great Wall measures more than 6000 Km in length. The height of the Wall is approximately 7.8 meters and the width is about 5.8 meters at the top. A strongly build battle fort accompanies each section of the wall, from which the soldiers can protect the wall and stop the attacks of the invaders.
Although, archaeologists are trying to confirm which section of the Great Wall was built first, it is said that the first section was constructed in the central area of Chin around 200 B.C. The remaining section of the Wall took many years to complete the entire Wall. The Great Wall Society of China thinks that the Chu people (who once ruled the states of chin) can be considered as father of the Great Wall. Initially, the wall was not built directly, in stead, there were smaller sections of the walls; each section was raised to protect the state it surrounded. The northern states which came under Chou Dynasty are said to have built these sections of walls to defend their states from the neighboring states and also from the tribal invaders.
According to the director of Institute of Archaeology of the Henan Academy of Social Science, Xiao Luyang said that the earliest section of the Great Wall that was built was an inverted "U" shaped wall with a length of about 500 miles and was across the counties of Yexian, Fangcheng, Lushan and Nanzhao in southwest Henan.
Some sections of the Great Wall are built up only using stones and no mortar at all and some sections are built using the combination of stones and bricks. The Great Wall runs through the mountains portion and even deserts. A battle fort or tower (which was built for the surveillance purpose) was built at the regular distance (about 50 meters) with the Great Wall. The battle forts served the purpose of aiding the soldiers for watching and shooting at the invaders.
Today, the Wall stands at its place even after hundreds of years of its construction. The size, shape and strength of the Wall have not deteriorated too much. The credit of it goes to each dynasty that ruled the states of Chin. Each dynasty that ruled the states of Chin showed high interest in keeping the Great Wall stronger which defended them from the invaders. It is said that the Ming Dynasty which ruled in 13th century, undertook a huge repairing work of the wall and it took nearly two centuries to complete the task. Ming Dynasty also built a huge section of the Great Wall which runs along the mountains northwest of Beijing.
The decision of joining the sections of Walls was taken when all the states unified near 200 B.C. A strong and longer Wall was made by joining all the section of the walls to defend Chin from the invaders from the Tsongnoo Tribes from the north side. The actual length of the Great Wall has not yet known because small sections of Walls are being discovered today also in excavation.