Green Switch Palace

The Green Switch Palace is a small palace found on the west side of the Donut Plains, unlocked by finding the secret exit in Donut Plains 2, in the game Super Mario World. Inside it is the Green Switch, which turns all Green ! Blocks tangible.

Green ! blocks contain valuable Feathers when hit. In later castles, a single green ! block appears before the boss door, giving Mario or Luigi one more power-up before facing a Koopa Kid.