Impel Down

Impel Down is the World Government's maximum-security prison for the most dangerous criminals and pirates. The name derives from The English verb 'impel', meaning to force.

It is located underwater in the middle of a Calm Belt. To get there with the greatest of ease, one must use a water current accessible by going through the Gates of Justice located at either the Marine Headquarters or Enies Lobby. By using this water current located between these three locations, the amount of time for traveling between these locations is also cut by a considerable amount.