Azkaban

Azkaban is a terrible place. Prisoners were for years guarded by Dementors, horrible creatures who have been described as "sightless soul-sucking fiends." They feed on positive emotions, which means that after spending much time in the prison, the prisoners lose all hope and all good feelings and thoughts. They are forced to relive the darkest, most horrible memories of their lives. Some go mad, others simply despair and die