ABSTRACT Any child that has been to a museum, gone stomping through a creek, or gazed at the stars knows that science learning isn’t confined to a classroom. Children are eager to explore the wonders of the natural world, and parents and teachers value the importance of science education—thus, The Children’s Museum of Indianapolis (TCMI) has collected science objects and conducted fieldwork since it was first established. During the 1930s, museum staff members drove equipment-laden Model T cars on expeditions known as Prairie Treks. Indianapolis schoolchildren were given the chance to venture to the western United States and investigate the plants and wildlife of the region. Campers learned to identify birds and animals, pan for gold, make plaster casts of dinosaur footprints, and collect fossils and rocks to add to the museum’s collection. The natural science collection at TCMI is composed of more than 10,000 unique objects that help foster both curiosity and enthusiasm for the sciences. Science is an intensely hands-on and investigative endeavor, and this is reflected in the scope and the use of the objects in the collection. Items related to zoology, botany, and geology provide core materials that are utilized throughout the museum in exhibits, programs, and interpretation. TCMI is closing in on its 100-year history. Its unique mission, as the world’s largest children’s museum, helps it to provide public engagement with the geosciences. Today each year more than 1.2 million visitors can experience programs ranging from self-guided discovery to active participation with scientists and their current research. Thousands have joined dinosaur excavations in the rocks of the Hell Creek Formation of South Dakota, prepped fossil materials in the Paleo Prep Lab, and even assisted in collection-based research.