Rainbow Road is a rainbow colored racing track floating in empty space that serves as the final race course in each entry of the Mario Kart series. The course's design and its surroundings vary from game to game. As such, it is also traditionally the most difficult track largely due to a lack of barriers to prevent racers from flying over the edge. The original Rainbow Road seen in Super Mario Kart features no guard rails of any sort, while other designs seen in later entries such as Mario Kart Wii feature barriers along some but not all sections of the track. Mario Kart 7 features both its own variation of Rainbow Road as well as a graphically updated version of the original.
Rainbow Road has also made appearances outside of the Mario Kart games in other racing games such as F-Zero X, albeit at a higher difficulty level, and with the same layout as in Mario Kart 64. Also, in the expansion version of F-Zero X, the music for the level was remixed to match the music from the Mario Kart 64 version. It also appears in Mario Hoops 3-on-3 as an unlockable basketball court and in Super Mario Galaxy 2 as the Rolling Coaster Galaxy, which bears a resemblance to the original Super Mario Kart version of the track.