What's going on under the ground? There are pipes, tunnels, and even roads underneath us! How do they get built down there? In this book, you'll learn how engineers design and build underground utilities, tunnels, and bridge foundations. The My Engineering Library series provides an introduction to a variety of engineering and design topics for beginning readers based on the Next Generation Science Standards (NGSS). From learning about how engineers design rockets to how they build structures underwater, these informative books present complicated information in easy-to-understand language with kid-friendly examples and diagrams. Each book includes an activity to support further comprehension.