It might even be a contender for biggest artwork ever. I originally planned to put this into an article about “what is art” – because, wow – i love it. It is about the Chinese equivalent of Google maps. But instead of satellite pictures, they make pixel art. Yes that’s right – all major cities have pixelled maps (click here for a German article about it).
Apparently they have this on several map services. The biggest one being baidu (click the second button on the left to enable pixel maps).

...by a lot of workers. Which works well because of cheap labor and lots of users in the densely populated areas.

One reason for the pixel approach is probably the censorship - overhead pictures are heavily restricted in China.