Mario Kart World is a big departure for the series in one crucial way - this time, it's open-world. Each track seamlessly connects to the next, and all of them can be found in the game's new Free ...

However, none of that would have been possible without Mario Kart Wii, which first hit Nintendo's motion-tracking mini-console 15 years ago today.

Mario Kart 8 Deluxe has passed a new milestone, as it is now Nintendo's best-selling game of all time--if you don't count one particular bundled game from the Wii era.