Cliff Spring Cave
“You know the Cliff Spring Cave on the far end of the lake? Some nasty ooze came spilling out of it with no warning at all! Now, our beautiful lake is contaminated. It's so yucky!”
The Cliff Spring Cave houses the second of the two secret areas located in Bianco Hills in Super Mario Sunshine. It is located on the northeastern side of the lake in Bianco Hills, and can be entered any time after and including Episode 6 in Bianco Hills. The opening of the cave is also the location of the main Turbo Nozzle Nozzle Box for this world, which will subsequently activate all others when unlocked. To reach the cave, Mario must follow the road to the Big Windmill and then jump across the lake and land on a few floating logs outside the cave, as the lake is polluted in the first level that it is able to be entered. After entering the cave, Mario will be presented with another secret area, which he must complete without the help of F.L.U.D.D., who is taken by Shadow Mario at the start of the secret level.
This level features multiple different traps including flipping blue and red platforms, giant glass blocks, and pushing arrows. Mario must rely only on his natural abilities to traverse the secret area, and must also master the Wall Jump in order to successfully get past the first glass block in the secret area. Like all other secret areas in the game, Mario can use F.L.U.D.D. only if he successfully clears the area for the first time.