Earth is the third planet in the solar system and the only known planet that supports life. In the Mazinger franchise it often serves as the main world that the main characters live on and often comes under attack from threats seeking domination over the planet such as Dr. Hell or the alien military the Vegan Empire.
Compared to most planets that usually have a single environment and ecosystem, Earth contains many environment from tropical rainforests, vast oceans, hot deserts, and freezing tundras. It contains many urban areas throughout the globe. The dominant species are humans, sentient lifeforms descended from ape-like ancestors.
Depending on the series Earth has a rich history of events such as a race of life forms that predated humans, an underground empire that built giant robots and cyborgs, or even the destruction of civilization.