The Green Martian Genocide was an event on Mars that led to the decimation of the Green Martian species with only two known survivors. The genocide was perpetrated by the White Martians another races of Martians that lived beneath the surface of Mars. The genocide brought about the end of the Green Martian civilization and secured White Martian dominance over the planet.
For a long time Mars had been at peace and the two martian races had been separated with the Greens living on the surface and the Whites living underground. For some unknown reasons the White Martians emerged onto the surface of the planet and directly sought to end the Greens with some fanatic conviction. The Greens tried to fight back but the Whites overwhelmed their defenses and destroyed any opposition to them.
The emergence of the Whites brought them into direct conflict with the Greens. The Whites ruthlessly subjugated the Greens and killed many outright including woman and children. The men were forced into labor to work for the Whites until their death. The killings was systematic and without mercy as the White Martians sought to bring an end to Green Martian race.