There is land. The problem is, it's green and covered in vegetation. Thankfully, it's a green surface layer and not billions upon trillions of plant objects. The dark green of the plants plus the blue of the atmosphere blends together. Get closer to the surface (and I mean almost the troposphere) and you'll see the difference between land and water. I've attached what it looks like if Atmosphere Visible is turned off in the renderer settings.
