Prison

Prison is a recurring type of location in the Final Fantasy series where criminals are held. It is always a mandatory type of location to visit.

Final Fantasy XII
Nalbina Dungeons are a part of the Nalbina Fortress which Archadians sealed off from the Fortress. People who fought in invasion of Dalmasca and Nabradia two years prior to the game events and those oppose Archadia. Vaan, Balthier, and Fran are thrown here after the events in Rabanastre at the beginning of the game.

Final Fantasy Crystal Chronicles: The Crystal Bearers
The Aerial Prison is located in the Prison Sands, and all high-security prisoners are taken there. It is actually a cover for a top-secret weapons operation by the Lilty army, led by Jegran, using crystallized humans as fuel for huge airships.