A 13,000 mile dragon of earth and stone winds its way through the countryside of China with a history almost as long and serpentine as the structure. The Great Wall began as multiple walls of rammed earth built by individual feudal states during the Chunqiu period to protect against nomadic raiders north of China and each other. When Emperor Qin Shi Huang unified the states in 221 BCE, the Tibetan Plateau and Pacific Ocean became natural barriers, but the mountains in the north remained vulnerable to Mongol, Turkish, and Xiongnu invasions. To defend against them, the Emperor expanded the small walls built by his predecessors, connecting some and fortifying others. As the structures grew from Lintao in the west to Liaodong in the east, they collectively became known as The Long Wall. To accomplish this task, the Emperor enlisted soldiers and commoners, not always voluntarily. Of the hundreds of thousands of builders recorded during the Qin Dynasty, many were forcibly conscripted peasants and others were criminals serving out sentences. Under the Han Dynasty, the wall grew longer still, reaching 3700 miles, and spanning from Dunhuang to the Bohai Sea. Forced labor continued under the Han Emperor Han-Wudi , and the walls reputation grew into a notorious place of suffering. Poems and legends of the time told of laborers buried in nearby mass graves, or even within the wall itself. And while no human remains have been found inside, grave pits do indicate that many workers died from accidents, hunger and exhaustion. The wall was formidable but not invincible. Both Genghis and his son Khublai Khan managed to surmount the wall during the Mongol invasion of the 13th Century. After the Ming dynasty gained control in 1368, they began to refortify and further consolidate the wall using bricks and stones from local kilns. Averaging 23 feet high and 21 feet wide, the walls 5500 miles were punctuated by watchtowers. When raiders were sighted, fire and smoke signals traveled between towers until reinforcements arrived. Small openings along the wall let archers fire on invaders, while larger ones were used to drop stones and more. But even this new and improved wall was not enough. In 1644, northern Manchu clans overthrew the Ming to establish the Qing dynasty, incorporating Mongolia as well, Thus, for the second time, China was ruled by the very people the wall had tried to keep out. With the empire's borders now extending beyond the Great Wall, the fortifications lost their purpose. And without regular reinforcement, the wall fell into disrepair, rammed earth eroded, while brick and stone were plundered for building materials. But its job wasn't finished. During World War II, China used sections for defense against Japanese invasion, and some parts are still rumored to be used for military training. But the Wall's main purpose today is cultural. As one of the largest man-made structures on Earth, it was granted UNESCO World Heritage Status in 1987. Originally built to keep people out of China, the Great Wall now welcomes millions of visitors each year. In fact, the influx of tourists has caused the wall to deteriorate, leading the Chinese government to launch preservation initiatives. It's also often acclaimed as the only man-made structure visible from space. Unfortunately, that's not at all true. In low Earth orbit, all sorts of structures, like bridges, highways and airports are visible, and the Great Wall is only barely discernible. From the moon, it doesn't stand a chance. But regardless, it's the Earth we should be studying it from because new sections are still discovered every few years, branching off from the main body and expanding this remarkable monument to human achievement.
二萬一千公里長的土石龍 綿延於中國鄉野之間 它的歷史幾乎與 蜿蜒的結構一樣長遠 長城一開始是好幾座夯土城牆 在春秋時代由各個諸侯國修建 以抵禦賽北的遊牧民族 並互相防衛 秦始皇於西元前 221 年 一統天下後 青藏高原及太平洋 成為國家的天然屏障 但北方的山嶺仍難防守 很容易受蒙古、土耳其 及匈奴的攻擊 為了抵禦胡人 秦始皇將前任君王 修築的小面城牆 加固結構並連接起來 因為此建築物從西邊的臨洮 延伸至東邊的遼東 這些城牆被統稱為「長城」 為了完成這項任務 秦始皇徵募士兵及平民 但他們並非全部都出於自願 秦朝有案可考的數十萬工人中 很多是被強迫徵召的農民 其他則是服刑的犯人 漢朝時代,此牆愈建愈長 達到 5955 公里 自敦煌橫跨至渤海 強迫勞動持續至漢武帝 長城變為惡名昭彰的苦難之地 當時的詩歌和傳說敘述著 工人被埋入附近的萬人塚 甚至是牆內的故事 雖然牆內並未發現人類遺骸 墓穴的確顯示許多工人 死於意外、飢餓及衰竭 這座牆的確令人生畏 卻非天下無敵 成吉思汗及其子忽必烈 於 13 世紀蒙古入侵時 都曾攻克牆頂 明朝於 1368 年掌權後 開始再加強防禦工事 進一步鞏固牆身 使用在地火窯製造的 磚頭與石塊 平均 7 公尺高 6.5 公尺寬 8851 公里的長城 間隔設置烽火台 一旦看到侵略者 升起的烽火及狼煙 就在台間傳遞訊息 直到援兵抵達 牆面上還有小的開口 讓弓箭手射擊入侵者 大的開口則拿來 丟擲石頭及其他東西 但是這面改良過的新牆還是不夠好 1644 年北方的滿族 推翻明朝 建立清朝 也合併蒙古 因此這是第二度 中國受原本想以牆抵禦的 外族統治 隨著帝國的疆界擴張到長城以外 築牆防禦失去了原本的目的 沒有定期加固的長城 失修荒廢 夯土受到侵蝕 磚頭及石塊則被盜竊 當建築材料 但是它的工作還沒結束 二次世界大戰時 中國用部分牆面抵禦日本攻擊 外界仍盛傳長城某些地方 現在還拿來做軍事訓練 但是今天 長城的主要目的是文化 長城為地球上大型人造結構之一 1987 年聯合國教科文組織 將其列為世界文化遺產 原本修築以排拒外人進入中國 長城現在每年要歡迎 數百萬的旅客 事實上,湧入的遊客造成長城損壞 致使中國政府啟動保護措施 它也常常被譽為 唯一可自太空看見的人造結構 可惜,這說法不對 在低軌道上,各種建築物 如橋梁、高速公路 及機場都為可見 長城僅為隱約可辨識 從月球看 則一點都看不到 但無論如何,地球才是 我們應該好好研究長城的地方 因為每隔幾年就會發現新的片段 從主體向外伸展 擴展這座非凡的歷史遺跡 成為人類偉大成就