Rainbow Road

Rainbow Road is the name of the last racecourse of the Special Cup in each of the Mario Kart games. These tracks are suspended in the starry night sky or outer space. Most contain few or no rails, putting racers at risk of falling, and each Rainbow Road also contains its unique hazards. Due to these obstacles, Rainbow Road is usually the hardest track in each Mario Kart game.

Super Mario Kart
This Rainbow Road lacks rails entirely and contains 90-degree turns. Rainbow-colored tiles cover the track's surface, and the yellow tiles conceal Coins and jumping humps. This course features flashing Thwomps which can, unlike normal Thwomps, wipe out a racer by touch as well as by crushing unless the racer activates a Star.

Super Mario Kart composer Soyo Oka considers this level's theme one of her favorite compositions.

Mario Kart 64
Rainbow Road is the longest race course in Mario Kart 64 at 2,000 meters and requiring around two minutes per lap. The track features a transparent multi-colored path and with Star-shaped rails running throughout the course. Neon-light pictures of the eight playable characters, plus a portrait of a Boo and a Mushroom in the distance, float in the void. Moreover, a big three-dimensional smiling Star lies in a section of the track. Roving Chain Chomps slide through the course in reverse, tossing into the air any driver who touches them.

The twisting course starts with a huge drop followed by a gentle uphill stretch, passing through a rainbow ring halo. After the ring, racers behold the flashing neon portraits while run through a pigtail bridge, following then towards another shallower drop. Racers turn around a corkscrew to reach a hairpin bend, and then a twisting stretch to go back to the checked line finally.

Racers can perform a large shortcut by making a timed hop to the left (or right, during Extra) during the drop at the beginning.

Mario Kart: Super Circuit
In Mario Kart: Super Circuit, Rainbow Road has rails at the start line. Edges of the course are lined with bounce-jumps. Astute racers can use Mushrooms to perform significant shortcuts. The track has falling stars that can make racers spin out and Thunder Clouds that will shrink anyone careless enough to drive under them. The Bowser's Castle from Paper Mario can be seen in the background. This track is equal with the course of Rage Racer Overpass City. This game also features the Rainbow Road course from Super Mario Kart without the flashing Thwomps.

Mario Kart: Double Dash!!
Dash Panels give a boost of speed to the racers in the Mario Kart: Double Dash!! version of Rainbow Road. This version of Rainbow Road also has rails in parts of the course. It features a helix and a pipe that shoots players to the highest point of the track after reaching the very bottom. It also contains floating sculptures of items, and rains stars that racers can pick up. It has the most pearl-like colors of all the Rainbow Roads. Additionally, the entire course is placed high above a city. The city it floats over could be Mushroom City because of the design of some of the buildings. When in split screen mode, the city and the item sculptures are removed. The theme music played in the course is a remix of the Rainbow Road from Mario Kart 64, and reappears in Super Smash Bros Brawl as an alternative music theme for the Mario Circuit battle stage.

Mario Kart DS
The Rainbow Road of Mario Kart DS has several rails on certain curves and includes a loop and a corkscrew. Those elements may have been added to ensure challenge; players can place items so their opponents could fall off the corkscrew or the loop. Some multi-colored Pipes and Stars appears in the surroundings of the stage. Additionally, the coloring pattern of this looks different from the other previous Rainbow Roads: here, the stripes on the track follow along it, instead of crossing the track.

Mario Kart Wii
The Rainbow Road of Mario Kart Wii is a new version of the rainbow-colored track. The track is located over the eastern parts of North America, as well as parts of Europe, Africa, and South America. The course begins on a 90 degree slope, located after the starting line. Multiple curves and trick pads appear, and the course features also a launching point, where players are shot away by a stylized Launch Star. The track shows a reminiscent of the Rainbow Road of Mario Kart DS, while visual style is based on Super Mario Galaxy. Star Bits appear in the background of the course. A corkscrew reappears not far from that Launch Star. Further cementing the fact it was inspired from Super Mario Galaxy is the fact the ghost is Princess Rosalina, and a Launch Star pattern is seen on the rails. If a player falls off, they will burn up in the atmosphere before being lifted up and brought back onto the track.

Mario Hoops 3 on 3
Rainbow Road is the unlockable third dribble race from the "challenges" section in the basketball game Mario Hoops 3 on 3. However, this Rainbow Road floats above the clouds and around a clock tower, and not much of the course is fully seen when playing. Podoboos and Bombs come out of holes similar to Bowser Castle.

Trivia

 * F-Zero X has a track named Rainbow Road. It imitates the Mario Kart 64 version of the Rainbow Road, having the same map of the track, and following it basically. It is described as a "Psychedelic Experience". Parts, though not all of it, are rainbow-colored. Unlike the original, it has no barriers in certain areas, and the neon Mario series decor is missing - instead, it just has a plain black background with a watery blue bottom to which careless drivers may fall. In addition, when racing the track with the 64DD expansion features, the background song is a heavy metal version of the Rainbow Road song heard in MK64. Of course, there aren't any Chain Chomps.
 * Rainbow Road is the only track in Super Mario Kart which is not numbered.
 * A portion of Good Egg Galaxy's music (from Super Mario Galaxy) is heard on Mario Kart Wii ' s Rainbow Road to match the environment of this course.