King Kai's Planet
King Kai's Planet is a fictional planet, located in the afterlife, at the end of Snakeway. It is home to the deity that controls the northern sector of the northern galaxy, King Kai. Even though it's a small planet, it has about 10x Earth's gravity, which caused the Saiyan Goku massive trouble when he first arrived there. Though Goku was born on a planet with similar gravity (Vegeta), and thus used to be familiar with this level of gravity, his stay on planet Earth and its considerably lower gravity, caused him to lose his familiarity with 10x Earth's.
 Plot involvement
King Kai's planet was first introduced in the early Saiyan Saga, after Goku sacrificed himself in the battle with his Saiyan brother Raditz. He was accompanied to the Check-in Station by the Earth's guardian Kami, who managed to convince King Yemma to allow Goku passage, onto the 1 million kilometer Snakeway, in order to seek King Kai's training. Training under elevated gravity caused Goku's power to raise to new heights, as well as mastering the deadly techniques Spirit Bomb, and Kaioken. After Goku's training, King Kai and his planet returned to the story sporadically, until the explosion of the villain Cell, destroyed it, forcing King Kai, along with Goku and his pets Gregory and Bubbles, to migrate onto Snakeway, and later to the Grand Kai's Planet.