The eighth wonder of the world, the longest in the world, "Wan Li Chang Cheng" ("Wall of ten thousand li") - the so-called at different times of the Great Wall. And though the last title we can assume the true size of the ancient Great Wall of China (there is 1 576 m), different sources name different numbers. According to some assumptions of its length does not exceed 4 thousand kilometers, on the other - it is more than 5 thousand kilometers.
The average height of the wall 6, 6 m (in certain areas up to 10 m), the width of the bottom of about 6, 5 m, top - about 5, 5 m. This width allows pass two horse carts. Throughout the Great Wall of China built casemates to protect and guard towers, and at the main mountain passes lined fortress.