Peach's Castle (Super Smash Bros.)
From the Super Mario Wiki
Peach's Castle is a stage in Super Smash Bros., and is heavily based off of Princess Peach's actual castle. The castle is actually a very small arena suspended in the air. In actuality, the stage may just be a piece of land that is part of Princess Peach's Castle, as the actual castle can be viewed far below the arena. This arena has a moving board that wends into the castle and comes out on the other side, making temporary platforms on both sides. It also has two Bumper-like platforms at the top, which will stop players from being knocked out of the stage. There is also a Bumper in the middle, which moves back and forth. A Lakitu also makes a cameo appearance in the background after a few minutes.
Although the original Peach's Castle stage did not appear in Super Smash Bros. Melee, a similarly-named stage which was situated upon the actual castle appeared, and was referred to as Princess Peach's Castle.