The Great Wall of China was built to stop intruders from invading the country. Construction began more than 2,000 years ago. The wall took more than 1,000 years to build. Find out more in The Great Wall of China, a title in the Structural Wonders of the World series. These books identify some of the world's best-known structures, exploring their history, the people responsible for their creation, and the science behind their construction. Each title features informative text, colorful photographs and maps, and a timeline detailing the steps toward construction.