Lost Kingdom

The Lost Kingdom is an area in Supra Mayro Bross - Legend of the Lost Kingdom and is the first level of the game. It could be ruled by Princes Pesh along with the Musshrom Villadge, but it may not be true. The Lost Kingdom level was "reinmagined" in Supra Mayro 64. The Lost Kingdom appears to be in the sky.

Supra Mayro Bross - Legend of the Lost Kingdom
In the game, the Lost Kingdom is the first and only level before the Castle. It is the grass level, see more here about the level.

Supra Mayro 64
In the game, the Lost Kingdom is recreated as a level although it is still in the style of a 2D platformer (as it has paper-thin objects). It now has two Gumbas instead of one. The MS-Paint style objects have now been made more "cubical" than its 2D counterpart.

Trivia

 * The Mushroom Kingdom in Super Mario Bros looks less "floaty" than the Lost Kingdom in Supra Mayro Bross.
 * The floating grass in the level looks like it has a face.
 * It might be true that the reason this is lost is that it is in the sky, which is proven by the clouds being in the middle of the screen instead of way above it. However it is not known how it stays in the sky and Mayro and Gumbas can still breathe up there.