The Great Wall of China

Introduction

Name:The Great Wall
Location:Beijing of China
Length: 8,851.8 km (5,500 miles)
Construction Period: About 2,000 years from the Warring States Period (476 BC - 221 BC) to Ming Dynasty (1368-1644)

The Great Wall, one of the greatest wonders of the world, was listed as a World Heritage by UNESCO in 1987. Just like a gigantic dragon, the Great Wall winds up and down across deserts, grasslands, mountains and plateaus, stretching approximately 8,851.8 kilometers (5,500 miles) from east to west of China. With a history of more than 2000 years, some of the sections are now in ruins or have disappeared. However, it is still one of the most appealing attractions all around the world owing to its architectural grandeur and historical significance.

Before the use of bricks, the Great Wall was mainly built from rammed earth, stones, and wood. During the Ming Dynasty, however, bricks were heavily used in many areas of the wall, as were materials such as tiles, lime, and stone. The size and weight of the bricks made them easier to work with than earth and stone, so construction quickened. Additionally, bricks could bear more weight and endure better than rammed earth. Stone can hold under its own weight better than brick, but is more difficult to use. Consequently, stones cut in rectangular shapes were used for the foundation, inner and outer brims, and gateways of the wall. Battlements line the uppermost portion of the vast majority of the wall, with defensive gaps a little over 30 cm (12 in) tall, and about 23 cm (9.1 in) wide.

Communication between the army units along the length of the Great Wall, including the ability to call reinforcements and warn garrisons of enemy movements, was of high importance. Signal towers were built upon hill tops or other high points along the wall for their visibility.

If you go to China,the Great Wall is worth to visit！