It's a project of hint.fm, which invents "new ways for people to think and talk about data." Awesome.
Watersheds in America
This map simply and elegantly displays every watershed in America. It was a recent project from former Google engineer Nelson Minar that demonstrated "a complete example of how
to build a web map using tiled vector data."
As a non-tile-vector-data person myself, I'm not sure exactly what that means, but I would disagree with Minar's assessment that this map is not "particularly beautiful." As the below image and New England close-up illustrate, it's quite a striking demonstration!