The article reviews the evidence and implications of the Snowball Earth hypothesis, which posits that the Earth experienced periods of global glaciation, including ice sheets extending to low latitudes. The hypothesis challenges the traditional view that the Earth's orbital obliquity was high enough to explain low-latitude glaciation. Instead, it suggests that an unusual distribution of land masses in the middle and low latitudes, leading to a higher albedo, set the stage for snowball events. The hypothesis is supported by several geological and geochemical observations, such as the abrupt onsets and terminations of glacial events, the presence of cap carbonates, and the return of large sedimentary iron formations during post-glacial periods. The article also discusses the testing of the snowball hypothesis through carbon isotope stratigraphy and the analysis of cap carbonates, which provide evidence for rapid climatic fluctuations and the formation of anoxic environments. The snowball Earth hypothesis offers a comprehensive explanation for the complex and synchronous glacial events observed globally, suggesting that the Earth's climate was highly sensitive to changes in orbital parameters and greenhouse gas concentrations.The article reviews the evidence and implications of the Snowball Earth hypothesis, which posits that the Earth experienced periods of global glaciation, including ice sheets extending to low latitudes. The hypothesis challenges the traditional view that the Earth's orbital obliquity was high enough to explain low-latitude glaciation. Instead, it suggests that an unusual distribution of land masses in the middle and low latitudes, leading to a higher albedo, set the stage for snowball events. The hypothesis is supported by several geological and geochemical observations, such as the abrupt onsets and terminations of glacial events, the presence of cap carbonates, and the return of large sedimentary iron formations during post-glacial periods. The article also discusses the testing of the snowball hypothesis through carbon isotope stratigraphy and the analysis of cap carbonates, which provide evidence for rapid climatic fluctuations and the formation of anoxic environments. The snowball Earth hypothesis offers a comprehensive explanation for the complex and synchronous glacial events observed globally, suggesting that the Earth's climate was highly sensitive to changes in orbital parameters and greenhouse gas concentrations.