Here is one of the wonders of the world-the Great Wall of China. Your map of China will show you that this wall begins on the east at a bay of the Yellow Sea. It winds across mountains, rivers, and deserts, half the length of China. As the crow flies, this is about 1,200 miles long. But the wall is so crooked that it is about 1,500 miles long. It marks the boundary between China proper and Mongolia (mn-g´ l-å). It was built 200 years B. C. This means that it is 2,100 years old. It was 1,500 years old when Columbus discovered America. As you see, the wall is very tall and very thick. It is 30 feet in height and 25 feet in thickness. It is made of bricks, earth, and stones. Earth is placed between the outside layers of bricks and stones and is packed very hard. This great structure, if set down in the United States, would reach from Boston to Guthrie, Okla.; or from St. Paul, Minn., to Palm Beach, Fla. Six hundred million cubic feet of materials were used to build it. And it was all built in 10 years. One wonders still more, when he sees the kind of country the wall passes over, how this work could have been done. The clay and bricks were carried for miles and miles. Rivers had to be bridged. Mountains were climbed-cliff so steep that mules could not get over them. Why was it built? The Tartar tribes of Mongolia were constantly coming down on the Chinese. At last a Chinese emperor decided to stop these invasions. He called about him an army of engineers and builders, and the Great Wall began. When it was done, the Chinese soldiers could hold back the northern raiders easily. The view shows one of the famous gates in the wall, near Nankow Pass, north of Peking. The road here is the great highway between north and south China. Keystone ID: 14555 Note: All titles, descriptions, and location coordinates are from the original Keystone Slide documentation as supplied by the Keystone View Company. No text has been edited or changed.