From the Super Mario Wiki
A free-for-all on Hyrule Castle
Hyrule Castle is a lengthy stage in Super Smash Bros. based off The Legend of Zelda series. In the single-player mode, Hyrule Castle is the first stage the player battles on. During gameplay, a whirlwind will occasionally appear about every 30 seconds; any character in it is blown upwards, and sometimes out of the stage if sufficiently damaged. The castle also has a little shack at the far right end of the stage, which may act as an additional platform.
This level serves as Link's home stage in the game. In Super Smash Bros. Melee, a similar but much larger stage called Temple takes its place.