Columbia, also known as Nuna, was an ancient supercontinent that assembled approximately 1.8 billion years ago during the Paleoproterozoic era. Its formation was driven by global collisional orogenies that welded together almost all of the Earth's continental blocks, including prototypic North America, Baltica, Siberia, India, and Australia. Measuring roughly 12,900 kilometers along its long axis, Columbia represents one of the earliest well-documented supercontinents. It remained intact for about 300 million years before beginning to fragment around 1.5 billion years ago, a rifting process that generated major rift valleys and new ocean basins, setting the stage for the assembly of Rodinia.