china great wall.the most impressive architectural feats in history

the most impressive architectural feats in history.The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials, the historical northern borders of China to protect the Chinese states and empires against the raids

Several walls were being built as early as the 7th century BC;[2] these, later joined together and made bigger and stronger, are collectively referred to as the Great Wall.

The Great Wall stretches from Dandong in the east to Lop Lake in the west, along an arc that roughly delineates the southern edge of Inner Mongolia. A comprehensive archaeological survey, using advanced technologies, has concluded that the Ming walls measure 8,850 km . This is made up of 6,259 km sections of actual wall, 359 km of trenches and 2,232 km of natural defensive barriers such as hills and rivers .Another archaeological survey found that the entire wall with all of its branches measure out to be 21,196 km (13,171 mi) Today, the Great Wall is generally recognized as one of the most impressive architectural feats in history.