1. Map CA, the underground isle map, area 3.
2. Map DB, map db C, area 1 (the whirlpool)
3. Map BE, the pit, (hidden tunnel)
4. Map DE, the tower ruins (hole beyond mummies)
There’s also the underground isle map in map CA’s Next Level. Location three has a tunnel leading to the sleestak underground.
And there’s a map of the lost world for the player characters to find in map GC, gc A 4.