5Get ready to experience over 165 million years of dinosaurs in Timeline Science: Dinosaurs With information backed by the Smithsonian Institution, this kit profiles the ferocious dinosaurs that walked earth during the Triassic, Jurassic, and Cretaceous periods. The fun doesn't stop there--modern dinosaur and fossil discoveries and today's dinosaur relatives are also included. After reading about these prehistoric giants, kids can unfold the timeline poster, use the included stickers, then build a T.rex skeleton