The home of the Guardian of Earth in Dragon Ball. Notable inhabitants have included Kami, Mr. Popo, and Dende.
Kami's Lookout is the location in which Earth's current guardian Dende resides and where Earth's former guardian Kami used to reside, the location was named in honor of Kami himself.
A room that exists as filler, this chamber is also known as Room of Time in both the Dragon Ball and Dragon Ball Z animes. Mr. Popo stated that the past, present, and future is operated and controlled for these rooms. The main function of the Pendulum Room is meant to send one or people's spirit through time to train. In Dragon Ball, Goku was sent back in time to learn from Master Roshi's former sensei Master Mutatio about manipulating one's ki. In one Dragon Ball Z filler episode; Tien, Yamcha, Chaotzu and Krillin go to a similar room where their spirits back in time to fight two past Saiyans, Shorty and Scarface. These rooms didn't appear in the original manga.
In an early Dragon Ball filler episode, it is also revealed that the Lookout has a teleporter or transporter machine that allows Kami or anyone to go wherever they want to on Earth. Kami is rarely shown using this, but the most notable case was in Dead Zone during the initial struggle with Garlic Jr.
A room featured prominently in Dragon Ball Z, it is in a different time dimension, where a day outside is a year inside (or just one minute outside is six hours inside). It is used by many major characters, and Gotenks fought Super Buu in it. Piccolo destroyed the door during this battle in an attempt to lock Buu inside forever, along with himself and Gotenks, so it is impossible to get in or out of it now. However, Buu is able to escape by creating a portal by screaming at the top of his lungs, which Piccolo and Gotenks do after he escapes to let themselves out. Supposedly the room can only be used for up to 48 hours outside the chamber in one lifetime. If one were to break that rule, the doorway to the outside world would automatically vanish, thus trapping the trainee(s) inside for eternity. However, in Buu or Gotenks' case, they would simply bust out as they had done before, thus nullifying this effect. Goku alleged that only two people can enter at a time, however this was proven false, as Goten, Trunks, Piccolo, and Super Buu were able to be inside all at once.
While all of the above is on top of the lookout, there are two different things inside the lookout: In Dragon Ball Z, the very bottom of the lookout (where the Nyoi-bō fits in) is connected to all the winds of the world, to get there, one must go through a sacred area known as the Shinsenkai where all the past Kami of the earth exist.
In Dragon Ball GT, it was just empty, allowing Goku and Uub to have their battle without harming the Earth .