Google has updated the base maps used in Google Maps so that viewers can get a quicker, more comprehensive look of the lay of the land. Terrain will now be depicted on the Google Map's base map, along with color gradients to show varying vegetation, and labels to show natural land formations.
Above you'll see a section of Southern Asia before the update to the base map. It's pretty boring, mostly white, and doesn't show a lot of terrain information. Below, you can see the updated version of the same map. In the updated version, the vegetation is much more pronounced, along with terrain, such as mountains.
I'm trying to decide if the timing of this is to compete with Apple's Maps or not. I'm leaning towards no, and that this is just a simple progression of Google Maps trying to be all they possibly can be. With that said, the changes are a great addition and bring the maps more into line with the paper maps of yesteryear.