Princess Peach's Kingdom (also known as Peach's Kingdom, Peach's Plains, or the Grassland World) is a first and grassland-themed world with grass hills, big and small mushrooms, flowers, and plains. Even enemies that includes, Goombas, and Koopa Troopas. The boss of this world is Larry Koopa and False Bowser.
This is the layout of World 1 from New Super Mario Bros. which based on this world map, even a background is like a New Super Mario Bros. Wii styled grassland with Princess Peach's Castle which Mario starts next to it.
World 1-1 Grass Plains
A first and grassland level based on World 1-1 in Super Mario Bros. with Goombas and Koopas.