Great Wall of China!

Story of the Great Wall is said to start from the spring and autumn periods when seven powerful states showed at the same time. To defend themselves, they all built walls and stationed troops on the border. At that time already the total length of the wall reached 3107 miles, belonging to different states.

In 221 BC, Emperor Qin absorbed the other six states and defines the first common kingdom in Chinese history. To increase its authority and defend the newborn females in the north, he ordered connecting the walls once built by the other states as well as adding some parts of their own. Thus was formed the long Qin's Great Wall, which started from the eastern part of today's Liaoning Province and ended at Lintao, Gansu Province.

In the Western Han Dynasty, the Huns became more powerful. He courts began to build more walls on a larger scale in order to consolidate the frontier. In the west, was the wall along the Hexi Corridor Yumenguan Pass and Yangguan Pass built. In the north, was Yanmenguan Pass and Niangziguan Pass in Shanxi created. Many more parts of the wall extended to Yinshan Mountain and half of the old Silk Road was along his wall.

The Northern Wei, Northern Qi and Northern Zhou Dynasties all built their own profiles, but on a smaller scale than the walls of the Han Dynasty. The powerful Tang Dynasty saw peace between the northern tribes and central China most of the time, so few Great Wall sections built in this period.

Ming Dynasty is the top of building materials in Chinese history. Ming suffered a lot by disturbances from minority strains such as Dadan, tufan and Nuzhen. Ming court from its first emperor to last ceaselessly built walls in the north. The main line started from Jiuliancheng near the Yalu River in the east to Jiayuguan Pass in the west and measured over 4600 miles. In addition to adding several miles of its own, Ming emperors ordered the extension of the walls of previous dynasties into double-line or multi-line walls. For example, added out of Yanmenguan Pass three big stone walls and 23 small stone walls. Eleven garrisons were distributed along the main line of the wall. The countless walls, fortresses and lookout towers made the country strongly fortified. In the early Qing Dynasty, some parts of the walls were repaired and several sections were extended. This great engineering work stopped in the middle of the Qing Dynasty.

Because of its long history, natural disasters and human activities, many parts of the Great Wall severely damaged and disappearing. Being a world famous engineering project and witness the rise and fall of Chinese history, the Great Wall needs us to take immediate steps to protect it!

The Great Wall is not a continuous wall, but a collection of short walls that often follow the top of the mountains on the southern edge of the Mongolian plain. The Great Wall of China, known as "long wall of 10,000 Li" in China, stretching over 8,850 kilometers (5,500 miles).

A first set of walls designed to keep Mongol nomads out of China, were built of earth and stones in wood frames under the Qin Dynasty (221-206 BC).

Some additions and changes to these simple walls over the next millennium but the major construction of the "modern" walls began in the Ming Dynasty (1388-1644 CE).

Ming fortifications were established in new areas from the Qin walls. They were up to 25 feet (7.6 meters) high, 15 to 30 feet (4.6 to 9.1 meters) at the base, and from 9 to 12 feet (2.7 to 3.7 meters) wide at the top ( wide enough for marching troops or wagons). Periodically was vaguely stations and watch towers up.

Since the Great Wall was discontinuous, Mongol invasion had no problems with breaking the wall by going around it so that the wall failed and was eventually abandoned. Moreover, a policy that mollification during the subsequent Ching Dynasty, who sought to reassure the Mongol leaders through religious conversion also helped to reduce the need for the wall.

Through Western contact with China from 17 through the 20th century grew the legend of the Great Wall of China together with tourism on the wall. Restoration and rebuilding took place in the 20th century and in 1987 the Great Wall was made a World Heritage Site. Today, a portion of the Great Wall about 50 miles (80 kilometers) from Beijing receives thousands of tourists every day.

Can you see the Great Wall of the Moon? :

For some reason, seems some Urban Legends to come out and never disappears. This legend even appears as an erroneous Trivial Pursuit question. The explanation? Many are familiar with the claim that the Great Wall is the only manmade object visible from space or from the moon to the naked eye. This is simply not true.

The myth that could see the Great Wall from space originated Richard Halliburton's 1938 (long before people saw the Earth from space) book Second Book of Marvels said that the Great Wall is the only manmade object visible from the moon.

From a low Earth orbit, many artificial objects are visible on site, such as roads, ships at sea, railways, cities, fields of crops, and even some individual buildings. While a low orbit, the Great Wall can certainly be seen from space, but it is not unique in this respect.

But when they leave the earth's orbit and acquiring an altitude of more than a few thousand miles, no man-made objects are visible at all. NASA says, "The Great Wall can barely be seen from the Shuttle, so it would not be possible to see it from the moon to the naked eye." Thus it would be difficult to spot the Great Wall of China or other objects from the moon. Moreover, from the moon, even continents are barely visible.

With regard to the origin of the story The Straight Dope's Pundits Cecil Adams says: "Nobody knows exactly where the story got started, although some believe it was speculation by some bigshot during an after-dinner speech in the early days of the space program. "

"Everything you can see from the moon is a beautiful sphere, mostly white (clouds), some blue (ocean), patches of yellow (deserts), and every once in a while some green vegetation. No man-made object visible at this scale. Actually once leaving Earth's orbit, and only a few thousand miles away, no man-made object is visible at this point either. "