The Cenozoic Era is the most recent geological era, spanning from about 66 million years ago to the present. It follows the Mesozoic Era and is characterized by significant changes in climate, geography, and the evolution of mammals and birds. The era is divided into three periods: the Paleogene, Neogene, and Quaternary. During the Cenozoic, the continents moved to their current positions, and the Earth's climate cooled, leading to the development of ice sheets in Antarctica. This era also saw the rise of humans, with the first Homo sapiens appearing around 300,000 years ago, marking a significant milestone in the evolution of life on Earth.