King Dedede's Castle
From the Super Mario Wiki
Kind Dedede's Castle is a major location in Super Smash Bros. Brawl. It is located in the World of Trophies just below the desert and the mountains and caves. During the Subspace Emissary, Dedede kept his three trophies here (Luigi, Ness and the princess trophy). However, after he puts a badge on the three of them, the roof of the castle starts falling. One piece of the roof lands on his head and knocks him out, unconscious. Then, it is shown that it was Bowser and his Koopa Troop where the ones who destroyed the roof. Bowser and his troop hop in the castle, take the princess trophy and rush out.
Minutes later, the Ancient Minister flies in here and his R.O.B.s set up a Subspace Bomb. The bomb explodes, swallowing a large part of the castle. However the Luigi, Ness and King Dedede trophies (when the roof fell, Dedede turned into a trophy) somehow manage to survive and later, near the end of the game, they are found very near Dedede's Castle. After turning back to life, they head on out to stop Tabuu.