Odin and his brothers killed Ymir. Only two giants survived the flood of Ymir's blood: Ymir's grandson, Bergelmir (son of Thrudgelmir), and his wife. Odin and his brothers used the body to create earth. His flesh filled Ginnungagap; his hair became trees; his eyebrow became Midgard his bones became mountains; his teeth and bone fragments became stones; his blood became lakes and seas. Ymir's skull became the sky, with four dwarves holding it up. Maggots from his flesh became the race of dwarves.