"For thousands of years, the Great Wall of China has stretched across China's Northern provinces. It winds like a giant, sleeping dragon from the Pacific coast in the east to the Gobi Desert in the west. But it's not the only wall in China. Learn abou the buidling techniques used, the empires who constructed them, and what their pruposes were over the centuries in this informative book. Put your walking shoes on and get ready to explore all the interesting...

"Thousands of years ago, ancient engineers came up with a way to cross obstacles that prevented people getting from one place to another. They built a passageway under the ground called a tunnel. A tunnel sounds simple. After all, it is just a tube built through dirt or stone. But building a tunnel is one of the hardest challenges an engineer can face. This scientific text highlights the origin of the first tunnels, the greatest tunnel builders, the...