The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials, generally built along an east-to-west line across the historical northern borders of China to protect the Chinese states and empires against the raids and invasions of the various nomadic groups of theEurasian Steppe.
Several walls were being built as early as the 7th century BCE; these, later joined together and made bigger and stronger, are now collectively referred to as the Great Wall. Especially famous is the wall built 220–206 BCE by Qin Shi Huang, the first Emperor of China. Little of that wall remains. Since then, the Great Wall has on and off been rebuilt, maintained, and enhanced; the majority of the existing wall is from the Ming Dynasty (1368–1644).
Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration. Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, and the fact that the path of the Great Wall also served as a transportation corridor.
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 (5,500 mi). This is made up of 6,259 km (3,889 mi) sections of actual wall, 359 km (223 mi) of trenches and 2,232 km (1,387 mi) 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).
#48 Forbidden City
The world’s largest palace, the Forbidden City, stands at the heart of Chinese history, as the home to the emperors for 600 years. And it’s full of secrets. This documentary goes behind closed doors to explore this extraordinary palace-city and to discover the clues to its creation.
Unique access to the latest conservation works uncovers evidence hidden in locked halls and high in the mighty roofs, revealing a ruler who governed by fear but also created an exquisite and enormous work of art and technology. Tests on the paints reveal trade with Europe, and the programme experiments with an ice road to move an entire marble stairway.
And another huge experiment tests the Forbidden City to destruction, as a giant scale model is placed on a seismic shake table to replicate the earthquakes that shook Beijing and to explore the design secrets that enabled the Forbidden City to stand up to the greatest shocks on earth.