The Paleogene is the first period of the Cenozoic era, beginning about 66 million years ago and ending about 23 million years ago. The Paleogene period lasted 43 million years. The name of this period means "born ancient." The period began immediately after the great Mesozoic extinction. Life rapidly tried to occupy the space freed after the extinction of reptiles and other ancient animals. The main events of the period were the development of mammals, birds, and flowering plants. The Earth's map continued to change. It was during the Paleogene that India began its collision with Eurasia, leading to the growth of the largest and highest mountain systems on Earth - Tibet and the Himalayas. But there was a more important event that affected the entire subsequent history of the planet - the last fragments of Gondwana: Australia, Antarctica, and South America split and moved apart. As a result, Antarctica found itself at the pole surrounded by cold waters, the circumpolar Antarctic current closed, and the southern continent began to be covered with ice. This, in turn, led to a significant cooling of the climate throughout the planet about 34 million years ago. The Paleogene saw the appearance of many new species of animals and plants, including the first true mammals (placental), including primates, as well as various types of birds, fish, and insects. The development of flowering plants led to a rapid growth of diverse vegetation, including the formation and widespread distribution of the first tropical rainforests (jungles). The Paleogene is famous for animals such as Paraceratherium and Entelodon, it was the time of formation of the first whales and small rodents, bats, and the most diverse birds. The Paleogene period is usually divided into three epochs, each of which has its scientific name: Paleocene (66-56 million years ago), Eocene (56-34 million years ago), and Oligocene (34-23 million years ago). Overall, the Paleogene period was a time of important events in Earth's history that led to the gradual formation of modern flora and fauna.