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Radiant Emerald is the unlockable fifth stage in Sonic R. It is the only course which has to be unlocked, accomplished once you place 1st in all of the races on the Grand Prix mode. It is a magical rainbow course surrounded by crystals that swirls around planets through outer space! The ring gates here contain massive shortcuts, so use them to your advantage. Of all the courses in the game, this is easily the longest and most straightforward of the lot, and even if you open the shortcuts, completing one lap will still take a while. It is the only track to contain no Chaos Emeralds or Sonic Tokens. By default, this course's theme is Diamond in the Sky. However, if you are to play as Super Sonic here, Super Sonic Racing will play instead. This course is similar to the famous Rainbow Road courses from the Mario Kart series.