What city do you find the prison bottle in ORAS?

In Pokémon Omega Ruby and Alpha Sapphire (ORAS), the prison bottle can be found in the city of Sootopolis. Specifically, it is located in the Cave of Origin, which you can access during the storyline related to the Legendary Pokémon Kyogre or Groudon. The prison bottle is used to contain the Pokémon Hoopa.