Secret Treasure Cave

Up near the Graal Administration Park there is a crack in the cliff.
You can access a secret cave by placing a bomb there.
NOTE: You cannot yet find the treasure.

Start at the "unstick me" location.

Go along the left path until you reach the corner and some tables.

Go up from this corner along the path until you reach Ol' Man Nelson.

Go up and to the left a little bit until you see a big archway.

Do not go in that, but follow the outside wall left until you find a crack in the cliff.

Blow a hole in the cliff with a bomb.

You can now go inside the cliff.

You can also go through the waterfall to find a man digging for treasure, but you cannot find it.