Why was the Great Wall of China built?

              We all have heard the name of the Great Wall of China. This is the longest wall of the world, being more than 2,400 kilometers (1,500 miles) long. Its height ranges from 4.57 to 9.2 metres (15 to 30 feet) while thickness is 9.75 metres (32 feet). It was built of stones and bricks. The construction of this great wall was started in the year 221 B.C. and it took almost 15 years to complete this work. Can you imagine what the necessity of constructing such a huge wall was?

               This great wall was built to protect China from Mongol invaders. About the year 246 B.C., China was divided into small provinces. King Shih Huang Ti united different provinces of China into an empire. To the North of this empire lived barbaric Mongols and the king feared that they might attack his empire any time. To protect China from this danger, he ordered the construction of a huge wall. So, a wall starting from Shahi Kuan in the bay of Pohai to Chaikuman in Kansu was constructed. A road ran along the wall and signals would be sent quickly along it by patrolling soldiers.

               Did the king achieve his goal? Unfortunately – no, because the wall was broken at many places and Mongols got an opportunity to attack China. The purpose of constructing the wall could never be fulfilled.

               The Great Wall of China is one of the very few man-made objects that are visible from the moon.