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Eocene

The early Eocene (Ypresian) is thought to have had the highest mean annual temperatures of the entire Cenozoic Era, with temperatures about 30° C. Forests thrived and trees grew even in polar regions. Eventually, the Eocene became cooler and drier. As India continued to drift northwards, pushing against the Eurasian continent, the mass of rocks thrust up between them formed the Himalayas.