Perhaps some of the most iconic extinct species, Dinosaurs are a diverse group of reptiles that first appeared in the fossil record 240 million years ago at the dawn of the Triassic Period. Their reign continued unchallenged for two other distinct periods, the Jurassic and the Cretaceous, home to some of the most famous examples like Triceratops and T. rex. Dinosaur fossils have been found on every continent, including Antarctica, and now you can add one of these incredible pieces of prehistory to your personal collection to appreciate and share their stories with others.