The Majestic Great Wall of China: A Journey Through Time

Made mostly of earth and stone, the wall stretched from the China Sea port of Shanhaiguan over 3,000 miles west into Gansu province. In some strategic areas, sections of the wall overlapped for maximum security (including the Badaling stretch, north of Beijing, that was later restored during the Ming Dynasty). From a base of 15 to 50 feet, the Great Wall rose some 15-30 feet high and was topped by ramparts 12 feet or higher; guard towers were distributed at intervals along it.