What was happening to the landmasses in the Tertiary Period Briefly?

During the Tertiary Period, which lasted from about 66 million to 2.6 million years ago, significant geological and climatic changes occurred. The continents continued to drift towards their current positions due to plate tectonics, leading to the formation of mountain ranges like the Himalayas. Additionally, the climate transitioned from warm and tropical to cooler and more variable, influencing the evolution of flora and fauna. This period also saw the diversification of mammals and birds as they adapted to changing environments.