From Cassius Comics

An island nation that presented itself to the world as a haven for mutants, Genosha in fact built its economy on enslaving mutants, both native ones and those that foolishly travelled to the country. This slave trade was eventually overthrown by the X-Men, and the country became a third world nation. Years later, when Magneto took the world hostage, the UN appeased him by giving him Genosha to run, this time as a true mutant nation. The country was later attacked by an army of wild Sentinels sent by Cassandra Nova, resulting in the extermination of almost the entire population, totalling over one million deaths. Reconstruction efforts within the shattered nation proved to be ineffectual until the arrival of a new group of workers, including Charles Xavier (Professor X) and Callisto. They were soon joined by Magneto, who sought Xavier's help in curing his comatose daughter Wanda (the Scarlet Witch), who had recently suffered from a devastating mental breakdown. Most recently, the wild Sentinels (now in one giant form) were reactivated by the machine Danger, who attempted to use them to detroy Xavier and the X-Men; the Sentinel stopped its attack when Kitty Pryde revealed the atrocities that it had already committed against the people of Genosha. Shocked by the sheer number of deaths on its conscience, the Sentinel retreated into outer space.