The period known as the Age of Dinosaurs is referred to as the Mesozoic Era, which lasted from about 252 million to 66 million years ago. This era is subdivided into three periods: the Triassic, Jurassic, and Cretaceous, during which dinosaurs emerged, thrived, and eventually became extinct. The Mesozoic was marked by significant geological and climatic changes, leading to the diversification of flora and fauna, including the rise of reptiles and birds. Dinosaurs, with their varying sizes and shapes, became the dominant terrestrial vertebrates, shaping ecosystems and evolving until their mass extinction at the end of the Cretaceous period, paving the way for mammals' rise.