World 3 (Super Mario World 2: Yoshi's Island)
From the Super Mario Wiki
World 3 is a world in the game Super Mario World 2: Yoshi's Island and its remake Yoshi's Island: Super Mario Advance 3. It is a jungle-based level. Its mid-boss is Prince Froggy; its main boss is Naval Piranha. Its secret level is Go! Go! Morphing!, its extra level is More Monkey Madness, and its bonus level is Drawing Lots. Although almost all the levels are jungle themed, there is one level titled The Cave of Harry Hedgehog, which takes place in a cave.
- The level point of 3-5 on the map is surrounded by cave-like terrain, even though 3-5 is not a cave level. 3-6 is a cave level and its level point doesn't have that terrain surrounding it. Similarly, 3-3's level point also has the 'cave', but it isn't a cave level either. This could mean that the levels in World 3 were originally going to be in a different order, or that other ideas were going to be used for those levels.