In this Opinion Article, we argue that tropical regions are, in fact, hot spots of extreme microbial diversity. The scope of the topic is vast and while this paper cannot be seen as exhaustive, it will hopefully serve to stimulate research interest in the reader to explore this fascinating area of microbiology and promote knowledge sharing and scientific collaboration. The article discusses the following points: (i) what extremophiles are and how useful they are to biotechnology; (ii) the importance of molecular techniques for extremophile identification due to their unculturability; and (iii) extremophile research performed in areas of different environmental conditions in Rio de Janeiro, Brazil.