Dig up fossils, discover crystal caverns, and uncover hidden treasures buried deep beneath the Earth! Join Rocky Diamond and his drilling squad on an underground expedition through dinosaur fossil beds, luminescent crystal caverns, ancient archaeological sites, and mysterious underground worlds -- all the way down to the Earth's core. An Underground Adventure is an interactive search-and-find STEM picture book packed with rainbow gemstones, ancient artifacts, hidden creatures, and long-lost treasures just waiting to be found. Innovative die-cut pages reveal a new layer of the Earth with every turn, building to a giant fold-out finale with one last spectacular discovery. Richly detailed illustrations reward curious readers with new surprises every time they revisit the adventure, blending search-and-find play with real concepts in geology, paleontology, and archaeology.