Great Wall of China
The Great Wall of China is a very old stone wall in China which was built to protect the north of the empire of China from enemy attacks. It is the longest structure humans have ever built: stretching approximately 6,400 kilometres long. The wall begins at Shanhai Pass and ends in Lop Nur. It is a UNESCO World Heritage Site.
The Great Wall stands 5 people wide and 20 people high.
Several walls, referred to as the Great Wall of China, have been built. The first was built in the 5th century BC. The most famous wall was built between 220–200 BC by the first Emperor of Imperial China, Qin Shi Huang. Little of this wall remains. It was much farther north than the current wall. The current wall was built during the Ming Dynasty.
History[change | edit source]
The First Emperor of China started the Qin Dynasty. The Xiongnu tribes in the north of China (who are also called the Huns) were his enemies. Because the land in some parts of China is easy to cross, Qin Shi Huang began building the Great Wall to make it more difficult for the Xiongnu to invade China.
Other dynasties in China worked more on the wall and made it longer. The Han, Sui, Northern and Jin Dynasties all repaired, rebuilt or expanded the Great Wall. During the Ming Dynasty, major rebuilding work took place, where sections of the Wall were built with bricks and stone instead of earth.
Construction and Rebuilding of the Great Wall[change | edit source]
Builders used materials nearby so some parts of the wall were made out of mud, straw, and twigs. Thousands of workers lost their lives from giant falling stones, exhaustion, disease, animal attacks, and starvation. The workers who lost their lives were buried in and under the Great Wall.
Visibility from space[change | edit source]
Rumours about astronauts being able to see the Great Wall from the moon are false. While the Great Wall has shown up in radar images taken from space, scientists are not sure whether it would be possible for astronauts to see the wall with a naked eye. One astronaut who spoke about not being able to see the Great Wall from space was Neil Armstrong who said:
I do not believe that, at least with my eyes, there would be any man-made object that I could see. I have not yet found somebody who has told me they've seen the Wall of China from Earth orbit. ...I've asked various people, particularly Shuttle guys, that have been many orbits around China in the daytime, and the ones I've talked to didn't see it.
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References[change | edit source]
- Construction of the Great Wall
- Norberto López-Gil. "Is it Really Possible to See the Great Wall of China from Space with a Naked Eye?". Journal of Optometry 1 (1): 3–4. http://www.journalofoptometry.org/Archive/vol1/pdf/02%20Vol1-n1%20Letter%20to%20the%20Editor.pdf.
- "China's Wall Less Great in View from Space". NASA. 2005. http://www.nasa.gov/vision/space/workinginspace/great_wall.html. Retrieved 2008-11-21.