The article discusses the unique ability of archaea, one of Earth's most ancient life forms, to thrive on hydrogen through special enzymes known as hydrogenases. These microorganisms have evolved strategies to extract energy from hydrogen gas, allowing them to survive in harsh environments like boiling hot springs and deep underground where no other life forms can exist. Additionally, some archaea, known as methanogens, produce methane in animal intestines, contributing to greenhouse gas emissions. The article highlights the potential for learning from archaea's hydrogen economy to develop more sustainable solutions as societies transition away from fossil fuels. Furthermore, the article delves into the history of life on Earth, suggesting that hydrogen played a pivotal role in the evolution of eukaryotes, the ancestors of animals, plants, and fungi. The merger of an archaeal cell and a bacterial cell, driven by the efficient exchange of hydrogen gas, led to the evolution of eukaryotes over billions of years. Despite modern eukaryotes losing the ability to use hydrogen, traces of ancient archaea and bacteria still exist within our cells, shaping the complexity of life on Earth. Researchers are exploring the potential of biological hydrogen catalysts, such as streamlined hydrogenases found in archaea, as a more efficient and cost-effective alternative to current industrial catalysts that rely on precious metals. By understanding how archaea have harnessed the power of hydrogen for billions of years, scientists aim to develop innovative solutions for a sustainable energy future, drawing inspiration from some of the oldest life forms on our planet.