This is a video released by MetalBallStudios (previously) comparing the sizes of various video game maps. The video starts with the 9km² map of Grand Theft Auto III, and ends with a 4,096,000,000km² map of Minecraft (which is a significant jump from the previous 161,600km² map of The Elder Scrolls II: Daggerfall). I'd be lying if I told you I actually learned anything watching it, but some might argue I'm actually incapable of learning. Just ask any of my college professors. "He slept through almost every class." Haha, sometimes I wouldn't even wake up until the middle of the next class, different professor and everything.
Keep going for the video.
Thanks to Jessie H, who's not convinced that was the best way to visually compare the sizes of things.