Sakaar
Sakaar is an artificial planet created by the Grandmaster. It is the fourth planet in the Tayo System, and the only inhabited planet in the system. The planet is orbited by two satellites: Aakar and Sabyr, also called the Broken Moon. It is surrounded by numerous wormholes that deposit debris, waste and other objects from other parts of the universe.
Sakaar is the homeworld of the Sakaarans, and is also inhabitted by many individuals of other sapient species from accross the Universe who were stranded on the planet by the wormholes.
There are no native plants, although the planet is home to a wide variety of mushrooms and fungi.
Original Timeline
In the original timeline, Thor and Loki became stranded on Sakaar, where they encountered Bruce Banner who had also become stranded there. In escaping from the planet, they also triggered a slave revolt, leading to the Grandmaster being overthrown.