The Ancient Prison Ruins can be reached by going down a sand whirlpool in Palu Wasteland, south of Kara Kara Bazaar.
Cave Location
The Ancient Prison Ruins can be reached by going down the sand whirlpool at -3100, -3063, 0008. It is in the Palu Wasteland, which you can reach by going south from Kara Kara Bazaar.
Cave Features
In the cave, you can find Luminous Ore Deposits and regular Ore Deposits, as well as Brightbloom Seeds, Hightail Lizards, and Hearty Lizards.
You can use Ultrahand to flip the lever and open the bars. There are Gibdos throughout the area beyond the bars.
There is a statue with a sword pointing to another lever. Flip the lever to open two of the nearby bars. One of the cells next to the lever has a hole in the floor. Go down through the hole, then crouch to go through the low passage in the area. Then go east until you can go south. You reach a large area with an Electric Chuchu and a Gibdo up ahead, and some ore deposits.
Through the bars in the west of this area, you can see this cave's Bubbulfrog. Go to the southwest corner of this area and walk up the stone slabs in the floor to go through the hole in the ceiling. You will reach a hallway with a lever at the end, but before you use it, go down the hole to the right of where you came up through the floor, and you will reach the area with the Bubbulfrog.
Back in the hallway with the lever at the end, be warned that the floor next to the hole will collapse if you walk on it. Use Ascend if needed to go back up to the hallway. You can flip the lever at the end of the hallway to make a shortcut back to the statue holding a sword that you saw earlier.
Go down through the hole where the floor collapsed, and you find another statue holding a sword. Go to where the sword is pointing, and you will see a shrine beyond the bars. Use Ascend to go through the ceiling, open the chest to get a Gerudo Scimitar, then use Ultrahand to move the stone slabs that are blocking the hole in the floor. In the hole, you find a lever. Flip it to make the statue in the wall move to the side. Go through to find Chichim Shrine.