
Stadium in Pokémon Stadium
Stadiums are buildings with large open interiors, typically serving as locales in which Pokémon battles are held.
The ReBoot Multiuniverse[]

Concept of apartment complex in Mainframe's Stadium
The Pokémon Stadium was actually built by the Binomes in Mainframe after the stressful day in which Bob and Dot got into a lethal tiff prompting Akari and her Pokémon to leave the System temporarily, mostly for the weekend. There was a domed structure in which the Pokémon, and some denizens, can observe their training bouts along with a tall apartment complex where Mr. Mime functioned as the receptionist. It's located at the right corner of the System, far enough away from Lost Angles.
There was also a large storage of sundries, mostly made by Shuckle and Parasect along with gathered Berries to replenish a Pokémon's health; with the large structure of the complex and similar functions, it reminds Akari of the department store in Goldenrod City. It was then abandoned after the power down to stall Gigabyte, the Web War, the Viral War, and Megaframe, until there was the system crash as Akari and her Pokémon made a hasty visit to gather all last-minute supplies.