World 2 (Super Mario 3D World)
From the Super Mario Wiki
World 2 is the second world of Super Mario 3D World.
It has ? Blocks and a 1-Up Mushroom scattered around the map. The world contains five standard courses, a Mystery House, a Sprixie House, and a Castle. The boss of this world is Boom Boom. After finishing the Castle, the yellow Sprixie Princess will create a Clear Pipe to World 3.