Dive into an exciting new world through submarines and sonar! The world beneath our oceans' surfaces is dark, cold, and mysterious. It's also a critical ecosystem. Scientists use high-tech underwater vehicles and sound-based technology to see the unseen, map the unknown, and learn about new species in the deepest parts of the ocean. Created in collaboration with the Smithsonian Institution, this STEAM book will inspire curiosity about deep-sea creatures and corals. It features a hands-on STEAM challenge that is ideal for makerspaces and takes students step-by-step through the engineering design process. Make STEAM career connections with career advice from actual Smithsonian employees working in physical science fields. Introduce engaging science topics to older readers with this STEAM book that is perfect for secondary students or ages 10-14.