The Cenozoic Era, also known as the Age of Mammals, began 66 million years ago and continues to the present day. It is characterized by the diversification and evolution of mammals, as well as the emergence of modern flora and fauna. Other synonyms for the Cenozoic Era include the Tertiary Period, the Quaternary Period, and the Age of Mammals. These terms are often used interchangeably, although some scientists and educators prefer to use the more specific Tertiary and Quaternary designations. No matter what it is called, the Cenozoic Era continues to fascinate researchers and individuals interested in the history of life on Earth.