Have you heard of the Great Wall of China ? This wall is one of the Seven Wonders of the World . It is the longest wall in the world, and is more than 2,400 kilometers (1,500 miles) long. Its height ranges from 4.57 to 9.2 meters (15 to 30 feet) while its thickness is 9.75 meters (32 feet). It is built of stones and bricks. The construction of this great wall started in the year 221 B.C. and it took almost 15 years for completion.
The Great wall of China
This great wall was built to protect china from Mongol invaders form the north. Around the year 246 B.C, china was divided into small provinces. King Shih Haung Ti united different provinces of china into an empire. To the north of this empire lived the barbaric Mongols. To protect china from the attacks of these Mongols, he ordered the construction of this huge wall. This wall runs form Shai Kaun in the bay of Pohai , to Chaikuman in Kansu . A road runs along the top of the wall for soldiers to patrol.
For centuries, the wall kept out these Mongols, but at the end they conquered china and made it a part of heir vast empire. Therefore the purpose of building it remained unfulfilled.
The Great Wall of China is one of the very few man made objects that are visible form the moon.
