Great Wall of China (began 7th Century BCE)
Despite the legend, the Great Wall of China is not actually visible from space – that’s a rumor started in 1923 by National Geographic magazine. But it is an impressively long wall, stretching about 21,196 kilometers (13,171 miles). It moves with China’s mountainous terrain, curving up and around the hillsides, and incorporates natural barriers like rivers and cliffs. Guard towers periodically interrupt the wall’s flow.
Defensive parapets and crenels top the wall along its ‘superhighway.’ A walkway along the top of the wall allowed soldiers, messengers, and equipment and uninterrupted path between strategic points, moving armies and troops quickly along the terrain. The Great Wall has come to symbolize China’s empire and its long-term strength, even if it wasn’t completely successful in keeping out all enemies (especially the Mongolians!).
