Zeal Dungeon (CTP)
Chrono Trigger Prerelease
Zeal Dungeon is an unfinished dungeon in Zeal and one of the most interesting Prerelease finds. Its purpose is unknown; it may have been the original holding cell for Crono's party after the first battle with Dalton. Players can find it by using the Walk Through Walls code and walking through the bookcase in Schala's room in Zeal Palace. It may take a few tries.
The exit at the top of the main hall leads to the throne room (near the throne), while the exit at the bottom left leads back to Schala's room. This suggests that perhaps the party needed a secret way to the throne. This might have been eschewed in the final version for powering up the pendant to use on the sealed door. The destination of the middle staircase is unknown, though presumably two of them led to the other two areas of the Zeal Dungeon. The most incomplete part does lead back to the main Zeal Dungeon hall. Two bridges (seen in the bottom right of the map below) were meant to extend to allow access around the map (thanks to The Cutting Room Floor for deducing this).
From: Locations (CTP)