This video explores how understanding Earth's early atmosphere and microbial life in Yellowstone's Lower Geyser Basin can reveal clues about how the first breath of oxygen appeared on our planet. Before the Great Oxidation Event, Earth's environment was vastly different, and microbes played a crucial role in this transformation. By studying geothermal features and ancient microbial processes in Yellowstone, scientists can gain insights into the evolution of early life and the development of Earth's oxygen-rich atmosphere.