The Cryogenian is a geological period that lasted from about 720 to 635 million years ago, during the late part of the Neoproterozoic Era. This period is notable for its extreme glaciations, often referred to as "Snowball Earth," where ice sheets may have covered much of the planet's surface. These conditions significantly impacted Earth's climate and environment. During the Cryogenian, the planet experienced dramatic changes that set the stage for future life. The end of this period saw the emergence of multicellular organisms, paving the way for the Ediacaran biota. The Cryogenian is crucial for understanding Earth's climatic history and the evolution of life.