Princess Peach's Castle/First Floor

The first floor of the castle is accessed from the Castle Grounds. It contains Bomb-omb Battlefield, Whomp's Fortress, Jolly Roger Bay, Cool Cool Mountain, The Secret Aquarium, The Princess' Secret Slide, the Castle Courtyard, Bowser in the Dark World, and Tower of the Wing Cap.

The First Floor also has doors leading to the Second Floor and Basement, but they can only be unlocked with keys gained by defeating Bowser.