Bowser Castle 1

Bowser Castle 1 is a race course from Super Mario Kart. It is a stone road residing in a pool of lava. The most dangerous obstacles are the Thwomps. They appear in groups of four. The Thwomps stay in the air during the first lap, then try to crush the players afterwards. They can also be a simple barrier on the ground. Another danger is the lava. There are gaps of lava that can be crossed with use of the yellow jump lines. If the player jumps in the wrong direction, however, it is possible to fall into the lava. There is no real shortcut in this course, however the player may use the zippers halfway on the track. Since they aren't used by computer drivers, it can help to pass them and save time.

Mario Kart: Super Circuit
The course reappears again in Mario Kart: Super Circuit. It is the fourth and final race in the Extra Mushroom Cup. It uses the background appearing in GBA Bowser Castle 1. It has an extra item box to the right of the bend that comes before the first lava hops. The Thwomps are not present in this version of the track.

Trivia

 * The music played here (and subsequent Bowser Castle courses) sounds very similar to the final boss theme in Super Mario World.