Why does Odin have only one eye?
The king of the Norse gods gave an eye in exchange for wisdom. He liked to wander around in Midgard, the land of humans, and he thought it would be great if he could just stay in Asgard and see everything without having to walk around. After a perilous journey, Odin got to Mimir's Well, but knew he would have to pay a stiff price for a drink. Mimir demanded Odin's right eye, and the god ripped it out himself and handed it over. Then Odin saw everything, including the future.